Model Diameter(mm) Image View Microphone Interface
MD-B20904 Ø3.6x16.3 front view N/A USB 2.0
TD-B20903 Ø3.2x13.3 front view N/A USB 2.0
TD-B20908R Ø8.6x2 front view N/A USB 2.0
XD-B20903 Ø3.2x6.4 front view N/A USB 2.0
XD-B20904R Ø4.2x1.9 front view N/A USB 2.0