Sennheiser SpeechLine Digital Wireless SL Bodypack DW-4-US Wireless Transmitter

The Sennheiser 505900 is a SpeechLine Digital Wireless bodypack transmitter that gives presenters, lecturers, and trainers a simple way to deliver speech that sounds clear and natural in any room.

Pair it with an SL Headmic 1, an MKE 1 lavalier, or another compatible Sennheiser microphone, clip it to your clothing, and enjoy complete freedom of movement. The transmitter and receiver communicate with each other to choose the best frequency automatically and avoid interference, while AES 256-bit encryption keeps every conversation private. An LC display on the pack shows battery level, link name, and signal strength, and a conveniently placed mute slider lets you silence the mic instantly when needed.

The included BA 30 lithium-ion battery powers the unit for as long as 15 hours on a single charge. Recharge by docking the pack in a Sennheiser CHG 2 charger through the external contacts, or connect a USB cable when a charger is not nearby. A housing that is both lightweight and durable stands up to daily use without weighing you down.

This transmitter fits naturally into corporate boardrooms, university lecture halls, houses of worship, and event spaces where reliable speech reproduction matters more than complicated setup.

• Automatic frequency selection and interference management
• Compatible with SL Headmic 1 and MKE 1 microphones (sold separately)
• Rechargeable BA 30 battery delivers up to 15 hours of operation
• Two-way communication with receiver for real-time status feedback
• LC display shows battery level, RF strength, and link name
• AES 256-bit encryption protects the audio signal