R7108SB – FASSTest Bi-Directional Communication System S. Bus2 Port and 8 Channels for Conventional System Receiver. 24.9 mm x 47.3 mm x 14.3 mm. 0.98 in x 1.86 in x 0.56 in. 12.0 g / 12.0 g. 3.7 V to 7.4 V (Voltage Range: 3.5 V to 8.4 V).