Soft textile material feels like clothing on the skin Slim & streamlined connector design New enhanced user-replaceable battery mechanism 5k Hz coded transmission, compatible with most Polar products & compatible gym equipment in fitness clubs. Look for the Polar logo next time you go! Compatible with: FT1, FT2, FT4, FT7, FT40, FT60, FT80, RCX5, RS400, RS300X, RS100, CS300, CS200cad, CS10