The 3Dio comes in three models, FS ($499), FS XLR ($799) and FS Pro II ($1,999). The 3Dio FS and FS XLR models contain integrated and matched Primo EM172 mic capsules inside each of the pros- thetic ears. The capsules are small-diaphragm, omnidirectional condenser microphones. The 3Dio FS Pro II model contains integrated and matched DPA 4060 microphone capsules inside each of the prosthetic ears. A full 20-20k Hz frequency range and the high-sen-sitivity of the 4060 capsules make the FS Pro II ideally suited for professional studio recording and high-end binaural recording. Common features include a bass roll-off switch beginning at 160 Hz, a 5/8-inch microphone stand adapter, a 9V alkaline battery within the chassis, and polyurethane ears.