The Sennheiser SL Bodypack DW-4-US is a lightweight, digital wireless bodypack transmitter designed specifically for speech applications in business and educational environments. It features an unobtrusive design, easy-to-use operation, and compatibility with lapel and headset microphones for hands-free use. Operating in the license-free 1.9 GHz DECT band, it provides secure, reliable transmission with automatic frequency management and AES 256-bit encryption. Its rechargeable battery system ensures long operating hours with convenient USB recharging.