Radius T°™ Wearable Thermometer

Stay on top of their fever with a hassle-free continuous thermometer (3-pack of sensors)

4.8 out of 5 Customer Rating

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Radius T°™ Wearable Thermometer

Radius T°™ Wearable Thermometer

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Radius T°™ Wearable Thermometer

Now there's an easier way to see when a fever spikes, so you know when to take action.

  • Round-the-clock temperature tracking for up to 8 days
  • Comfortably worn on the chest
  • Can be used by anyone age 5+
  • Hospital-grade accuracy
  • Water resistant - can be worn while showering
  • Seamlessly sends data to mobile device via Bluetooth®*
  • Fully disposable after use
  • Three sensors per pack
Health Matters

Continuous Matters. Accuracy Matters. Privacy Matters.



Easily track and keep an eye on a fever over time

  • CONTINUOUS MEASUREMENTS: Hassle-free temperature measurements, 24/7 for up to 8 days
  • HIGH TEMPERATURE NOTIFICATIONS: Automatically sends readings to your mobile phone and notifies you if temperature is high
  • TEMPERATURE TRENDING: Continually see if temperature is trending up or down, so you can see how the fever is progressing
Radius T°™ Wearable Thermometer

Get Started with the Radius T° Continuous Thermometer

Radius T°™ Wearable Thermometer

Get Started with the Radius T° Continuous Thermometer

Remove sensor from pouch and pull tab to activate battery.

Choose an application site on the upper chest below the left collar bone. Make sure the site is hair-free, clean, and dry.

Remove plastic film from the back of the sensor.

Apply sensor to the site, and press around the adhesive to ensure it is secure.

Details & Specifications

What’s in the Box

  • 3 continuous temperature sensors (each wearable for up to 8 days & disposable)
  • Setup Instructions
  • Downloadable Masimo Radius T° mobile app
Radius T°™ Wearable Thermometer

Frequently Asked Questions

Radius T°™ Wearable Thermometer

Frequently Asked Questions

Radius T° disposable sensors are indicated for use on adults and children ages 5 and up. The sensors should not be used by people who experience allergic reactions to adhesive tape.

Yes, we offer complimentary ground shipping on all US orders.

You can return or exchange new, unopened Product purchased directly from Masimo within 30 days of the original purchase date. Please read our return policy for more details.

Radius T° comes with a two-year limited warranty. Please read our warranty policy for more details.

The sensor is water resistant (IP24 rating) – it can be worn in the shower but should not be submerged.

Radius T° is compatible with Android and iOS devices.
Specifically on phones it is compatible for iOS 13 and up, on display sizes 4.7inches and up.
For Android phones it is compatible on Android 6.0 and up, on display sizes 4.7inches and up.
Tablets are not compatible with the Radius T° system at this time.

Search for “Masimo Radius T” in the iOS App Store or Google Play.

Yes, a smartphone euipped with Bluetooth® is necessary to use Radius T°.

No, the Masimo Radius T° app is not available for tablets at this time.

Once the app is downloaded onto your smartphone, you do not need Wi-Fi or a cellular data connection. The wearable temperature sensor connects to your mobile device via Bluetooth®.

The sensor must be within Bluetooth® range of your phone to receive data. This distance can vary depending on the use environment, but can be up to 100 feet maximum distance with direct visual line of sight between the sensor and your phone.

Yes, the app can run in the background and continue to receive data collected from the sensor. However, do not quit the app or your temperature session will disconnect.

The app can only be paired with one sensor at a time. If you pair your mobile phone to a new sensor, any active connection to another sensor will be lost.

No, only one app can be paired to the same sensor at the same time.

Each sensor lasts for up to 8 days of continuous use. The light on the sensor will flash orange when the sensor battery is low. A flashing red light indicates the sensor battery is out of power and is no longer transmitting data.

To remove the sensor, gently peel off the adhesive from the skin.

Radius T° sensors are designed for removal and reapplication no more than one time over the life of the product. To re-apply:
(1) Clean and dry the sensor application site.
(2) Gently wipe the exposed sensor adhesive with an alcohol wipe and allow it to dry to restore the adhesive properties.
(3) Follow the steps in the Apply Sensor section of your Setup Instructions.
Each sensor should only be used on a single person.

Dispose of used Radius T° sensors in accordance with local laws for the disposal of products containing electronic components.

We do not collect nor do we download the data collected by the mobile application, which includes data you enter manually and temperature data from the Radius T° sensor. Your data remains on your mobile device and is deleted if you delete the application.

Your sensor stores historical temperature measurements which are communicated to the Masimo Radius T° app when your phone is in range with and connected to the sensor.

No personally identifiable information (PII) is stored on the Radius T° Sensor. Any user profile information you enter is only saved on the phone within the Masimo Radius T° app and is never sent to the sensor, nor is that information shared with Masimo.

Want to know more? Explore More FAQs


The color of the indicator light on your Radius T° Sensor can be used to understand device status and help troubleshoot issues:

Color Sensor Description Next Steps

No light

  • Sensor power is off.
  • Confirm battery pull tab has been removed to activate the battery.
  • Replace the sensor.



  • Sensor is on and waiting to pair with your mobile phone.
  • Follow instructions to pair with your mobile phone.




  • Sensor is waiting for you to confirm that desired sensor was paired to your mobile phone.

  • Successful pairing of sensor and mobile phone.
  • Mobile phone successfully receiving data.
  • Verify the sensor is properly attached to the wearer’s body so that mobile phone can receive data.



  • Low sensor battery
  • Consider replacing the sensor.



  • Depleted sensor battery
  • Hardware or sensor failure, sensor blinking board failure code
  • Replace the sensor.

If you have tried all of these steps but still have issues, please contact Masimo Customer Support.

Experience the Power of Masimo

Experience the Power of Masimo

      *Requires sensor to be in bluetooth range of the host app.
      †Mobile device must be within Bluetooth® communication range and connected to temperature sensor to receive continuous readings and notifications. When not connected to your phone, the Radius T° Sensor stores at least 8 hours of temperature readings and will transfer that historical data to your phone when you reconnect.

      Bluetooth is a registered trademark owned by Bluetooth SIG, Inc.
      Bluetooth range is 100 ft with clear line of site.