Mini APM V3.1 Flight Controller For ArduPilot Mega External Compass APM Condition:New Use APM firmware and ground station, no need to modify Dimensions:1.38 in x 1.38 in x 0.31 in (3.5 cm x 3.5 cm x 0.8 cm) Size: 35*35mm Due to the difference between different monitors, the picture may not reflect the actual color of the item. Please consider you mind or not before buying.