The Sennheiser SKM 500 G4 is a handheld wireless microphone transmitter compatible with the EM 300-500 G4 wireless receiver. It features an interchangeable microphone capsule design and is offered without a capsule included, so you can choose the one that best fits your application. The transmitter operates on an exceptionally wide 88 MHz UHF tuning range with 3520 selectable frequencies available. It provides up to 8 hours of operation on two AA batteries, with a transmission range up to 330 feet and a selectable 10/30/50mW RF power output for overcoming interference in difficult RF environments.