V.5.5 Flight controller board (FCB) has six ESC/Servo headers which allow Multicopter configurations from 2 to 6 rotors. There are also headers for thee aileron, elevator, throttle and rudder connections from your RC Receiver.

V.5.5 (FCB) has three adjustable potentiometers increase or decrease gyro gain for all three axis (Roll, Pitch and Yaw) and can be used to calibrate the ESCs and reverse the gyro directions if necessary during pre-flight setup.

The V.5.5 (FCB) has an on board In System Programming (ISP) header to enable easy firmware updates with a site recommended programmer. The on board Atmega168 chip gives users the extra space to load expanded firmware with higher refresh rates to enhance stability.

Murata piezoelectric gyros which are incorporated into the board design for extreme flight stability.

Specs.
Size: 50.5mm x 50.5mm x 23.5mm
Weight: 14.5 gram
IC: Atmega168 
Gyro: Murata Piezo
Input Voltage: 3.3-5.5V
Signal from Receiver: 1520us (4 channels)
Signal to ESC: 1520us (4 ESCs)