This is the Castle Creations CCBEC, 10 Amp Adjustable BEC. The CC BEC is a little device that eliminates the need for a receiver and servo battery pack. It draws higher voltage from the motor batteries and drops it to a voltage level that is suitable for your receiver and servos. This is required in applications which draw high power for multiple servos or use more than 3S motor packs, as most ESCs with linear BECs are not designed for these applications.

Specifications:
Current Output: Peak: 10 amps
Continuous: 12V input = 7 amps / 24V input = 5 amps*
Output Voltage: 5.1V - User may set output voltage from 4.8 to 9 using the Castle Link (sold separately).
Input Voltage: 5v to 25.2v (2S to 6S LiPo)
Length: 1.2” (30mm)
Width: 0.6” (15mm)
Height: 0.4” (10mm)
Weight: 0.4 oz (11 grams)