'The AirLine 77 UHF Headset System offers a true wireless experience with no beltpacks and no cables, allowing complete freedom of mobility. The system includes the AH1 headset transmitter, along with the CR77 receiver. The AirLine headset transmitters feature the Samson Qe Fitness and QV10e Vocal microphone elements. The Qe and QV10e headsets were designed to go around the back of your head rather than over the top. This allows the transmitter to be attached directly to the headband, out of the way and completely unobtrusive, while being comfortable and secure during performances or group fitness classes. Both the Qe and the QV10e are designed with unidirectional microphones and cardioid pickup patterns that reject feedback. The Qe Fitness headset is ideal for group fitness instructors who need a durable headset that will remain in place despite repetitious movement. The QV10e Vocal headset has a microphone element that's perfect for singers who need hands free performance. All of the AirLine transmitters operate on inexpensive and lightweight AAA batteries that offer 14 hours of operation on a single battery. The core of the receiver system is the CR77 true-diversity half-rack UHF receiver. It works flawlessly with all AirLine UHF transmitters. Featuring a front panel display with large multi-segment audio level and RF level LED meters, and a large rotary volume knob that allows easy adjustment of audio output, the CR77 takes all of the guesswork out making your wireless system perform. SPECIFICATIONS:XLR and unbalanced 1/4-inch outputs with mic/line level output switch Headset transmitter features power/battery LED, power switch and mute switch Headset condenser mic is sweat resistant and employs unidirectional cardioid pickup pattern for great sound True diversity UHF wireless headset system with PLL frequency control CR77 receiver features multi-segment audio level and RF level LED meters Squelch and volume control AC adapter and 1/4-inch to 1/4-inch cable included