A collection of answers to some of the most frequent questions we get asked. If you require further assistance regarding a product or about the service we provide please contact us.

Buying & Ordering

Purchasing our products is simple and straightforward. Check out our How to Buy’ page

If you are a school in the UK looking to buy direct from us you can do that on this website.  Simply add the products you want to the basket.  If you need help choosing you can use our product configurator on this page

If you are a school in the UK but outside UK mainland additional delivery charges will apply so please contact us to enquire or you can buy our products from many school supply companies [email protected]

We only sell our products at RRP on this website.  If you are a trade customer you can purchase separately using your agreed pricing structure.

After placing an online order, you will receive an email order confirmation. If you fail to receive this please call us on +44 (0) 3330110570, or email us at [email protected]

If you need to make changes to an existing order please call +44 (0) 3330110570 to discuss with us.  Depending on the status of the order it may not be possible to amend your order.

Though our Trolleys and Frames are supplied with Trays additional sizes can be purchased separately.

Trolley/Frame HeightStandard Shallow TrayStandard Deep TrayStandard Extra Deep TrayStandard Jumbo Tray

Callero Custom Low Frame
Callero Custom Tall Frame181016844
Callero Trolley10408422
Callero Plus Trolley10658422
Callero Rover Trolley11705332
Dynamis Low Trolley7256321
Dynamis Mid Trolley9358422
Dynamis Tall Frame171516844
Science Under Bench Trolley7355211
Science Under Bench Frame7256321
Science Bench Height Trolley8606321
Science Bench Height Frame8257321
Science Mid Frame150013643
Science Tall Frame185017964


Delivery is FREE to the UK mainland for any orders over £30 (There is an £8.50 delivery charge for orders under £30). This excludes the Scottish Highlands & British Isles, Northern Ireland and Ireland and the Isle of Wight. If you are in the UK but outside of this delivery area please contact us for information on how to order at [email protected] or visit https://www.gratnells.com/support/how-to-buy. Unfortunately, we are not able to deliver outside the UK on this website, but please visit https://www.gratnells.com/support/how-to-buy for more information on how to order. We aim to dispatch orders placed through this website between five and 20 days depending on the products ordered.

We dispatch any orders that only contain standard trays within 5 days.  If you order trays in our made to order colours we dispatch within 20 days.

All other products including our frame and trolley sets are dispatched within 10 working days.


If you wish to return a product, please contact us within 14 days of receiving your order. The product needs to be returned to us in a resalable condition and you are responsible for repackaging the item, so please hold on to the packaging materials until you are certain that your order fulfils your needs. There will be a 20% restocking charge. No unauthorised returns are accepted.

Please inspect each box when your order arrives, and note any damaged or missing boxes. If you do have any damage or missing items please let us know by filling in the form on this page and we will arrange a replacement.


Our trolley and frame sets are available in a range of our best selling colours as complete sets. Empty frames and trays can be purchased separately although many tray colours are sold in pallets only on this site.

As we manufacture to order directly in our own factory we always have stock.  In the rare occasion a product involves a third party component we will contact you if you have placed an order that we cannot fulfil within 10 days.  Our made-to-order trays are not held in stock and are have a 20 day lead time to manufacture and dispatch.

Our runners can be integrated into a wide variety of furniture designs. For specific compatibility queries, have a look at our ‘Which Runner’ page which lists all runner types and applications

Buy any Gratnells product safe in the knowledge there is a five year guarantee on all products covering any defects in materials or workmanship.  In addition our trays come with a lifetime guarantee.  Please see our terms and conditions for full details

Please use the enquiry button on the product page to contact us about specific products

Care & Maintenance

You can download our tray cleaning instructions here

Customer Support

We’re here to assist you. Reach out to our dedicated customer service team for any queries, issues, or support needs you cannot easily find on this site.  Email us on [email protected] or call us on +44 (0) 3330110570

We are a UK based manufacturing company.  We supply our products on this site and through third parties, we do not have a physical store.

Trade Accounts

If you are interested in becoming a distributor for Gratnells or buying our products in bulk you can fill in this form and we will get back to you with the next steps


Gratnells Learnometer is designed in conjunction with Professor Stephen Heppell and his research team and is designed specifically for education. It tracks the seven key factors that determine air quality: temperature, humidity, light, sound levels, carbon dioxide, chemicals (VOCs), and dust (PM2.5). It has a fully customisable display, with an 8-hour battery backup. It can be used to constantly monitor your air quality, and connects to your wireless network so it can be managed remotely.

If you are based in the UK or Ireland you can buy a Gratnells Learnometer from this website.

To buy a Learnometer anywhere else in the world please contact us and we will either ship one to you or put you in contact with your local supplier.

Please note if we ship you a unit outside the UK you will be responsible for all local taxes, customs and duties.

The Learnometer requires a constant Wi-Fi connection, and a compatible iOS device with bluetooth (4.1) for installation. Learnometer is compatible with 802.11 b/g/n connections, with 2.4GHz. The App is compatible with iOS phones and iPads, running iOS 8 or later, and shortly (although not currently) with Android phones, running Android 4.3 (Jelly Bean) or later.

Learnometer subscribers have access to the Learnometer Dashboard.

Understand the health of your School at a glance

The dashboard’s colour-coded Learnometer Status Indicator allows you to understand the real-time status of each of your Learnometers at a glance. You can use the dashboard to compare air quality readings across multiple Learnometers to understand trends and potential source problems.

Receive alerts when your air quality needs attention

The Dashboard can send notifications when your Learnometers recognise issues with your air. Enable notifications for all Learnometer sensors relevant to your goals, and we’ll notify you if your air needs attention via email and through the notification panel in the dashboard.

Receive a weekly assessment of your School’s air quality

The Learnometer will send you a Weekly Report outlining your air quality status from the previous week as well as an analysis on where there is room for improvement.

The installation process is quick and easy. Each unit comes with a wall mount and a display stand for desks or tabletops so that it can be easily placed at breathing height. The wall mount includes a stick on pad or use the two screws and plasterboard anchors (also supplied) for a more permanent solution. We recommend selecting places close to a mains power outlet, and to avoid corners of rooms, areas with lots of direct sunlight, and places within one metre of a vent.

Once your Learnometers are placed, setting up each Learnometer takes about two minutes using our iOS  app. You must also register for a Learnometer Dashboard before you can install with the app.  Please note you will need a wifi connection to enable your Learnometer.

Your Learnometer is supplied with a one year free subscription to the online dashboard analysis software and cloud storage for all captured sensor data. After the first year, the subscription charge is £60 per year (£5 per month). This amount may change. Discounts for multi-year subscriptions are available. Your Dashboard will remind you when your subscription is due for renewal.

Without a subscription to the dashboard and cloud storage you will not be able to view and analyse both current or stored data from your Learnometer. Without a subscription the Learnometer is limited to only showing current sensor values via its built-in display

Learnometer is compatible with 2.4GHz 802.11b/g/n networks. For most users, reviewing the following aspects in your router’s settings will resolve any connection issue:

Frequency: Learnometer is only compatible with 2.4GHz networks. Learnometer will not discover or pair with 5GHz networks.

Mode: Learnometer works best with routers set to mixed access mode (802.11b/g/n). Due to the stricter access rules, Learnometer may not be compatible with 802.11ac or 802.11n-only modes at this time.

Channel: Generally, channels 1 and 11 have the least amount of interference. However, you may find that your Learnometer performs best on other channels, so it may take some tweaking and analyzing your environment to find your optimal configuration. Wi-Fi scanning services (such as NetSpot) can be helpful to find right channel for your environment.

If you’re trying to connect your Learnometer to a corporate or high-security network, we recommend taking a look at the following best practices. Here is an overview for the following:

Advanced Networking Highlights Network Encryption Methods Managing TCP Ports MAC Address Whitelists Testing for Network Compatibility

If you continue to run into trouble getting your Learnometer connected to your network, please contact us so we can help. We’re happy to troubleshoot over email or schedule a phone call at your convenience.

Advanced Networking Highlights

Your Learnometer requires outgoing TCP & TLS connections on Ports 8883 and 443.
The connection on Port 8883 is indefinite, the connection on Port 443 is intermittent.
For adding device-specific permissions, every Learnometer has a standard MAC-48 address listed on the back of the product.
Learnometer does not support networks requiring two factor authentication, login portals, or managed login networks. You may be able to connect your Learnometer to these networks by setting device-specific permissions (e.g. MAC Whitelists).

Network Encryption Methods

Learnometer recommends using a password protected Wi-Fi network. Because of the extra security it allows, we specifically recommend using WPA2 (WPA2 + AES) as the network authentication method. However, your Learnometer is also compatible with WEP, WPA, and open networks.
Your Learnometer is not compatible with WPA Enterprise, WPA2 Enterprise, or WPS encryption methods. Learnometer does not support networks requiring two factor authentication, login portals, or managed login networks–however, you may be able to establish a connection to these kinds of networks by adding your Learnometer’s MAC address to your network’s whitelist.

Managing TCP Ports

Basic security firewall configurations will commonly allow outgoing connections from all devices, but high security configurations may block all or a portion of this traffic. If your firewall is particularly restrictive, try adjusting your firewall’s policies to allow your Learnometer to make outgoing TCP connections on Ports 8883 and 443.
Your Learnometer uses one long-term secure communication protocol to send data back to Learnometer’s servers. After connecting to your Wi-Fi network, your Learnometer will open an ongoing TCP connection on Port 8883 to Learnometer’s servers, secured with standard TLS encryption. If severed, your Learnometer will continuously attempt to re-establish this connection.

Once per hour, your Learnometer will check for and download firmware updates when available. This check is done via a TCP connection using TLS security and HTTPS protocol, initiated on Port 442 to Learnometer’s servers.

All connections to your Learnometer are outgoing, no incoming connections are established.

MAC Address Whitelists

You can add your Learnometer to your network by whitelisting its MAC address (this method is sometimes referred to as MAC address authentication or filtering). You can find your Learnometer’s unique MAC address on the back of your product, it’s the 12-digit number starting with “70”.

Whitelisting your Learnometer by MAC address is often the best way to connect Learnometer to managed login access points requiring secondary authentication.

Testing for Network Compatibility

If you’re unable to connect to your Learnometer after trying the methods above, your network may be incompatible with Learnometer. While not the most elegant method, the quickest way to test the compatibility of your Wi-Fi network is to use a mobile hotspot.

By setting up a mobile hotspot or tethering to your phone, you’ll be able to quickly determine if your Learnometer’s connection issue is rooted in the advanced configuration of your Wi-Fi network.

However, if you’re unable to connect your Learnometer to the network created by your mobile hotspot network, it’s possible your Learnometer’s hardware may be defective. This rare situation is covered under our 1-year warranty and we’re more than happy to replace your product if needed.

Please note the url to log into your existing dashboard changed in January 2023.  The new address is https://learnometer.awair.cloud

The dashboard includes permissions and roles to share and limit access to the Learnometer units attached to your dashboard. It’s fully customisable, so you’ll have full control of which units each member will be able to view.

For example, if you’re managing several School campus you can choose to share the dashboard with the teachers in each school so they only see data for their specific location.

Dust (PM2.5): 0 to 1,000μg/m³ ±15μg/m³ or 15%TVOCs: 0 to 60,000ppb ±10%CO2: 400-5,000ppm ±75ppm or 10%Temperature: -40 to 125°C (-40 to 257°F) ±0.2°CHumidity: 0 to 100% ±2%Ambient Light: 0 to 64,000luxAmbient Noise Sensor: 40 to 95dB, A-weighted, slow-response

For ongoing use without a Wi-Fi connection to the dashboard and cloud storage you will not be able to view and analyse both current or stored data from your Learnometer. Without a Wi-Fi connection the Learnometer is limited to only showing current sensor values via its built-in display. You will need a Wi-Fi connection initially to set up your Learnometer.

The Learnometer’s display is fully customisable capable of showing values from all sensors. You can also fully disable the display so that your Learnometer cannot be tampered with locally.



Whether you require a single-column frame for a small area or a double or triple-column frame for increased storage capacity, Gratnells frames offer the ideal solution for keeping your materials neatly stored and easily accessible.



Create inspiring spaces where students can collaborate easily and effectively. Developed with design experts and school communities our furniture is designed to enhance your learning environment and provide optimal functionality.



The world’s no. 1 school tray, found in classrooms worldwide. Strong, tough and made to last our iconic trays come in a variety of colours and sizes to fit all types of classroom furniture. They are perfect for storing and organising essential classroom materials.


Tray inserts

Choose from our comprehensive range of tray inserts for storing smaller items such as pens or crayons. We also supply foam inserts which are ideal for storing calculators and fragile science equipment. Our new modular SortED range of inserts promotes student independence. It all adds up to a storage system that’s as comprehensive as you’ll ever need.