What the heck is a BEC? CC BEC Battery Eliminator Circuit 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. The CC BEC uses a Switch Rate method that is vastly more efficient than common circuits that sweat off much of your power through a heat sink.
Peak Current Output: 10 amps Continuous Current Output: @12 Volts input 7amps, @ 24volts input 5 amps ** Output Voltage: 5.1 volts out of the package, user may set output voltage from 4.8 to 9 using the Castle Link (sold separately). Input Voltage: 5 to 25.2v (2S to 6S LiPo) Length: 1.2" (30mm), Width: .6" (15mm), Height: 4" (10mm) Weight: 0.4 oz (11 grams)
**Ratings are determined with a 5mph airflow on the BEC. Servo connectors are not rated for current in excess of 5 amps. Users are encouraged to replace the connectors if more than 5 amp currents are anticipated. Modifications available below. For models containing digital servos (3D Heli's for sure!) which could demand currents 4 amps or more, increasing the output connection with double leads is strongly urged.
 "Castle Creations CC-BEC RX Battery Eliminator Circuit")