Polar H1 Heart Rate Sensor Provides continuous, accurate heart rate measurement using 5kHz coded transmission Soft fabric material feels like clothing on the skin Compatible with most Polar products* and gym equipment in fitness clubs. [*FT1, FT2, FT4, FT7, FT40, FT60, FT80, RCX5, RS400, RS300X, RS100, CS300, CS200cad, CS100 and all similar previous models] Anti-bacterial transmitter User replaceable battery