Bryton Rider 450 Guide De Démarrage Rapide page 57

Accuracy may be degraded by poor
sensor contact, electrical interference,
and receiver distance from transmitter.
The Bryton Smart HR Sensor contains a
user-replaceable CR2032 battery.
To prolong the life of your heart rate
monitor, detach the sensor and clean
the strap after every use.
CR2032
+
Hand wash after use.