AirLine Micro AH2 Earset Transmitter is a compact behind-the-ear wireless unit with an integrated omnidirectional microphone. It runs on an internal lithium-ion rechargeable battery, delivering up to 10 hours of operation and recharging via USB DC input. A single multifunction button handles power, mute and volume control. The transmitter features a coating for protection against moisture and perspiration. Channel variants are labeled K1, K2 and K3; dimensions are 171 × 14 × 58 mm and weight is 22 g.