Through Authenticate 
Features
Operating voltage range: DC 2.5V～5V.
Receiving frequency: 5 KHz ± 10%.
Receiving distance range: 80-120 cm / 130-150 cm.
Good anti-interference ability.
It has good compatibility and can be applied to most of the current market wireless heart rate chest straps around 5KHz.
Heartrate detection range 40~240 RPM
