System Specifications


Sensor glucose assay method
Amperometric electrochemical sensor
Sensor glucose reading range
40 to 400 mg/dL
Sensor size
5 mm height and 35 mm diameter
Sensor weight
5 grams
Sensor power source
One silver oxide battery
Sensor data
Up to 14 days
Sensor memory
8 hours (glucose readings stored every 15 minutes)
Operating temperature
50 °F to 113 °F
Sensor Applicator and Sensor Pack storage temperature
36 °F to 82 °F
Operating and storage relative humidity
10-90%, non-condensing
Sensor water resistance and ingress protection
IP27: Can withstand immersion into 3 ft (one meter) of water for up to 30 minutes. Protected against insertion of objects > 12 mm diameter
Operating and storage altitude
-1,250 ft (-381 meters) to 10,000 ft (3,048 meters)
Radio Frequency
2.402-2.480 GHz BLE; GFSK; 0dBm EIRP
Sensor transmission range
20 ft unobstructed
Please refer to the User's Manual for updates to the information.

Blood glucose assay range
20 to 500 mg/dL
Reader size
95 mm x 60 mm x 16 mm
Reader weight
65 grams
Reader power source
One lithium-ion rechargeable battery
Reader battery life
4 days of typical use
Reader memory
90 days of typical use
Reader operating temperature
50 °F to 113 °F
Reader storage temperature
-4 °F to 140 °F
Operating and storage relative humidity
10-90%, non-condensing
Reader moisture protection
Keep dry
Operating and storage altitude
-1,250 ft (-381 meters) to 10,000 ft (3,048 meters)
Reader display timeout
60 seconds (120 seconds when test strip is inserted)
Radio Frequency
Near Field Communication (13.56 MHz RFID); ASK Modulation; 124 dBuV/m; 1.5 inch communication range; 2.402-2.480 GHz BLE; GFSK; 2dBm EIRP*
Data port
Micro USB
Minimum Computer Requirements
System must only be used with EN60950-1 rated computers
Mean service life
3 years of typical use
Reader cleaning and disinfection
The Reader has a mean use life of 3 years, which is 156 cleaning and disinfection cycles (1 cycle per week for 3 years).
Power Adapter
Abbott Diabetes Care PRT25611 Operating temperature: 50 °F to 104 °F
USB Cable
Abbott Diabetes Care PRT21373 Length: 37 inches (94 cm) Color: Yellow

Please refer to the User's Manual for updates to the information.

Security Measures and Quality of Service:

Security Measures:

  • The communication between the Reader and Sensor during a scan is a short range Near Field Communication (NFC) method which makes it difficult to interfere with or intercept during transmission. The transmitted data is protected by a proprietary data format, encryption, and memory map. The integrity of transmitted data is ensured by a cyclic redundancy check (CRC) generated by the Sensor and verified by the Reader. The communication between the Reader and Sensor for Alarm data is a standard Bluetooth Low Energy (BLE) connection. The pairing of the Sensor to the Reader is accomplished during activation with an authenticated login procedure that uses an Out-of-band key exchange (NFC). This prevents unauthorized devices from connecting to the Sensor. The transmitted data is protected by a proprietary data format and encryption. This prevents unauthorized devices from accessing the data if they are within range and intercept the transmission. Under normal operation, the industry standard BLE protocols allow for many users to be in the same vicinity. In the case where the connection is lost due to out-of-range or interference, reconnection is only possible with the authenticated Reader that activated the Sensor.

  • The communication between the App and Sensor during a scan is a short range Near Field Communication (NFC) method which makes it difficult to interfere with or intercept during transmission. The transmitted data is protected by a proprietary data format, encryption, and memory map. The integrity of transmitted data is ensured by a cyclic redundancy check (CRC) generated by the Sensor and verified by the App. The communication between the App and Sensor for Alarm data is a standard Bluetooth Low Energy (BLE) connection. The pairing of the Sensor to the App is accomplished during activation with an authenticated login procedure that uses an Out-of-band key exchange (NFC). This prevents unauthorized devices from connecting to the Sensor. The transmitted data is protected by a proprietary data format and encryption. This prevents unauthorized devices from accessing the data if they are within range and intercept the transmission. Under normal operation, the industry standard BLE protocols allow for many users to be in the same vicinity. In the case where the connection is lost due to out-of-range or interference, reconnection is only possible with the authenticated App logged in to the same LibreView account that activated the Sensor.

Quality of Service (QoS):

  • QoS for the FreeStyle Libre 2 Reader and Sensor wireless communications using NFC is assured within the effective range of 4 cm between the Sensor and Reader that is specified to occur within 15 seconds. QoS for the wireless communication using BLE is assured between the Reader and Sensor at regular 1-minute intervals. If connection is lost between the Reader and Sensor for 5-minutes, the connection lost symbol displays. If connection is lost for 20 minutes, the Reader alarms the user if the alarm is turned on. If connection is lost between the Sensor and the Reader, up to 8 hours of glucose results can be retrieved by performing a scan with the Reader. The Reader is designed to only accept radio frequency (RF) communications from recognized and paired Sensors.

  • QoS for the FreeStyle Libre 2 App and Sensor wireless communications using NFC is assured within the effective range of 1 cm between the Sensor and phone. QoS for the FreeStyle Libre 2 App and Sensor wireless communications using BLE is assured at regular 1-minute intervals. If connection is lost between the App and Sensor for 5-minutes, the alarms unavailable symbol displays. If connection is lost for 20 minutes, the App alarms the user if the alarm is turned on. If connection is lost between the Sensor and the App, up to 8 hours of glucose results can be retrieved by performing a scan with the App. The App is designed to only accept radio frequency (RF) communications from recognized and paired Sensors.