The RX22-4 is a four-channel infrared receiver, compatible with transmitters operating on the 2.3-3.8 MHz bandwidth. The sleek, comfortable design features a convenient rotary channel selector and an easy-to-use on/off/volume control. The RX22-4 can be used with mono or stereo headphones and earphones, or a neckloop. Dual infrared detectors provide maximum sensitivity and operating range. Four-channel selectable: 2.3/2.8/3.3/3.8 MHz; Operating range: 28,000 ft2 (2,600 m2) in singlechannel mode with TX925 or TX90; Ultra-sensitive IR receptors; Exceptional audio quality; 2 AA batteries provide 100 hours of operation; Low battery indicator; Signal-to-noise ratio: 60 dB; CE and RoHS approvalOptional Accessories:; BAT026 Rechargable Battery; EAR 013 Single Mini Earbud; EAR 014 Dual Mini Earbuds; EAR 022 Surround Earphone; HED 021 Deluxe Folding Headpone; HED 026 Rear-Wear Headphone.