The Sheepdog SD-AT-3.5C Coiled Police Listen / Receive Only Earpiece is compatible with shoulder speaker microphones that accept a 3.5mm plug. Designed with Public Safety in mind, the SD-AT-3.5C headset has Kevlar cabling and durable strain reliefs. Connects directly to shoulder speaker microphone. Equipped with metal clothing clip to secure earpiece to collar. Once connected, radio traffic becomes private as it is redirected from speaker microphone to the user’s ear. Be ready for any audio environment and all day comfort with the SD-AT-3.5C Listen Only Kit. The acoustic tube can be cut to desired length. Release the acoustic tube by turning quick-twist connector counterclockwise and pulling away from transducer. The tube can be cut above or below coil. Simply reattach elbow or quick-twist connector, push back into transducer, and turn clockwise to lock into place.