Williams Sound IR-RX20 Under-the-Chin-Style Infrared Stereo Stethoscope Receiver

Infrared Compatibility : Works with all Williams Sound 2.3 or 2.8 MHz infrared systems. Compatibility : Compatible with Williams Sound 2.3 or 2.8 MHz infrared systems. Dual Detector : Ensures consistent infrared signal reception for uninterrupted audio.

eBay