Designed to accurately monitor the temperature of mission critical refrigeration units, ensuring that the contents remain at the critical temperature required for your application. The ISL124B is battery powered, wireless and simple to install at any location.

  • Assist in ensuring optimal operating conditions in room environments

  • Battery powered

  • Wall bracket mounting options

  • Built in antenna
  • Temperature alarm threshold hysteresis

  • Temperature Edge Intelligence (thresholds – warning, alarm)

  • Available as a ‘data as a service’ offering

  • Configurable transmit interval for each mode (standard, warning and alarm)
  • Configured over the air from ISL LoRa™ USB dongle


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Long Battery Life

Our sensors have been designed to have a battery life of up to 10 years, so you don't have to worry about changing them frequently.


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Proactive Alarm System

Pro-active alerts ensure that your team can prevent temperatures breaching critical levels, and so safeguard patient well-being.


Proven Partner

Invisible Systems are trusted by clients in both the public and private sectors. You can rely on us to deliver an outstanding level of service.

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Real-Time Online

Together with Real-time Online, the sensors enable constant monitoring, deliver pro-active alerts on threshold breaches and generate bespoke reports.

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Simple Set-Up

Pro-active alerts ensure that your team can prevent temperatures breaching critical levels, and so safeguard patient well-being.


Low Costs

Choosing wireless sensors and a cloud platform enables you to reduce your installation and maintenance costs.



Configurable high/low thresholds allow different transmit intervals when thresholds are crossed providing advanced edge intelligence to the network, and enable alarms to be generated by Realtime-Online™.


Data from every sensor in your network is reported back through Invisible Systems Big Data architecture either to our Monitoring and Analytics platform Realtime-Online™, or to a partner cloud platform via our API, ensuring that your data is visible, actionable and valuable to your organisation.


The 124B transmitter connects to the cloud via Invisible Systems cellular LoRa™ gateways, providing low power, reliable communication and long battery life. Invisible Systems can provide their in-house built Realtime-Online™ cloud portal to make this an ideal low-cost end-to-end solution.


The ISL124B is a LoRaWAN certified device and Invisible Systems are members of the LoRa alliance. It offers both ABP and OTAA activation options and is designed to work with all LoRaWAN gateways and network servers.



Frequency/Band (LoRa): EU 868Mhz Other regions available on request

Frequency/Band (LoRaWAN): EU863-870 Other regions available on request

Expected range (line of sight): Up to 10km

Power: LoRaWAN 25mW (14 dBm) LoRa: 100mW (20 dBm)


Approvals: CE, FCC, IC, Other regions available on request

FCC ID: Contains module VPYCMABZ

ICID: Contains module 722C-CMABZ


Dimensions (mm): 70x70x24 (excl bracket)

Enclosure colour: White

Enclosure plastic type: ABS

Operating Temp Range: -20°C to +60°C

Battery: 1 x AA (2400 mAh)

Batteries type: Lithium Thionyl Chloride (Non rechargeable)

Expected battery life, 6 min Tx interval: Up to 1.8 years

Expected battery life, 6 hour Tx interval: Up to 10 years

Operating lifetime: Up to 10 years

Power type: Battery 3.6VDC


Measurement interval range: 10 secs - 60 mins

Tx interval range (multiple of measure intervals): 1 min - 6 hours



Measurement Range: -20°C to +60°C

Accuracy: ±0.25°C (typical)
±0.5°C (maximum)

Resolution/Step-size: 0.1°C

Drift: < 0.05 oC over lifetime

Sensor characteristics: Digital

Calibration: Optional



Digital Status Inputs: Has an internal magnetic reed switch that works with optional magnet accessory for door opening detection


Download Datasheet
We wanted to use the IoT approach to technology using a device placed in a fridge to allow us to continually monitor temperature, but also to flag up where breaches occur so we can respond to them then and there. We now have evidence to show that, 24 hours a day, our vaccines are being stored at the correct temperature Paul Brown, NHS Suffolk Primary Care
We were looking for a wireless system, one that allowed all users to log on from off-site, was flexible enough to allow grouping per PI of units and didn’t need dedicated server hardware/networking. The trial of the system was so simple and impressive that we kept it. Royal Holloway University
Invisible Systems solution is so easy to install, there is no need to interfere with other IT services. It was a non-invasive install and that was a primary factor in selecting it. I can log in from home, from holiday - it’s very user friendly. Noel Gavin, Maynooth University