The Sennheiser EW-DX SK (S1-10) is a digital UHF bodypack transmitter for lavalier, headset and instrument use in theatres, conference venues, broadcast and live production. It is part of Sennheiser's Evolution Wireless Digital EW-DX series, the multi-channel, rack-oriented step up from EW-D, and works with EW-DX EM 2, EM 2 Dante and EM 4 Dante receivers. This S1-10 version covers 606.2 to 693.8 MHz, so check the band is permitted where you operate. The transmitter delivers a 20 Hz to 20 kHz audio bandwidth, 134 dB of dynamic range and only 1.9 ms of latency, with Bluetooth Low Energy used for quick setup and sync from the Sennheiser app. Audio input is a lockable 3.5 mm jack for clip-on or headworn microphones and instrument cables. It runs on two AA batteries or the BA 70 lithium-ion rechargeable pack, operates from -10 to +55 degrees C, and measures about 63.5 x 85 x 20 mm without the antenna. It is sold as the transmitter only: microphone, receiver and rechargeable battery are purchased separately. Transmitter RF output is 10 mW ERP.