Features: Small Size 3" x 1.75" footprint Easy to Add Requires no power or user configuration 470-560 MHz Band-Pass Filter Compatibility Shure G50 and H5 Sennheiser A and A1 Sennheiser 6000/9000 Low Band Lectrosonics Blocks B19, B20 and B21 RF Venue Band-Pass filters help ...Features: Small Size 3" x 1.75" footprint Easy to Add Requires no power or user configuration 470-560 MHz Band-Pass Filter Compatibility Shure G50 and H5 Sennheiser A and A1 Sennheiser 6000/9000 Low Band Lectrosonics Blocks B19, B20 and B21 RF Venue Band-Pass filters help eliminate "out of band" signals that can saturate the front end of wireless microphone receivers, greatly improving dynamic range.