The Williams AV IR M1 is an infrared (IR) assistive listening product, transmitting audio as modulated infrared light rather than radio waves. Because IR light can't pass through walls, these systems keep audio confidential room-to-room and are immune to RF interference, which is why they're the standard choice for courtrooms, legislative chambers, and other venues where audio privacy is required. It belongs to the newer IR+ product line, which integrates Wi-Fi alongside infrared in a single transmitter/receiver platform for added flexibility. Typical installations include courtrooms, legislative chambers, theaters, and classrooms needing ADA-compliant, interference-free listening.