Acoustic tube earpiece 14&';&'; coiled cord and 2.5 mm connector Compatible with Signal 21 shoulder microphone or any radio/remote microphone with a 2.5mm earphone jack Designed to save your department money. Our durable listen only acoustic tube earpiece has a 14&';&'; coiled cord and a 3.5mm connector for any radio or remote microphone with a 3.5mm earphone jack. Also compatible with the Code Red Signal 21 shoulder microphones as well as most Motorola speaker microphones.table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; }