Acoustic Tube Earpiece with 14" or 26" cord and 2.5mm, 3.5mm and a threaded 3.5mm (M2) connector for any radio or remote microphone with a 2.5 mm, 3.5 mm, or threaded 3.5mm earphone jack. 2.5mm is used on most Kenwood Brand Shoulder Mics. 3.5mm is used on many devices including most Motorola Shoulder Mics. The threaded M2 is used on some Motorola radios and adapters.The connector cord includes Kevlar® reinforcement in the cord. The heavy-duty strain relief means longer service and less down time.