Shure BLX188E/SM31 M17: 662-686 MHz

Wireless dual fitness headset system with two SM31FH headset cardioid condenser microphone. The BLX188E/SM31 System with two SM31FH fitness headsets features a durable, industry-standard microphone cartridge in a comfortable headset design for hands-free performance combined with simple setup and an intuitive interface for performance you can trust in. With analogue dual wireless transmission. Frequency: 662-686 MHz