Sennheiser EW-D SK U1/5 - Digital pocket transmitter for EW-D wireless systems, frequency range U1/5: 823,2–831,8 / 863,2–864,8 MHz, transmit power: 10 mW, operation with 2x AA batteries or optional BA70 rechargeable battery, dimensions (WxHxD): 63 x 80 x 20 mm, weight: 120 g