BEC complete (includes receiver box cover and seals)Overview Traxxas recommends the High Output BEC, or battery eliminator circuit, as a required accessory when installing the Traxxas #2255 High Torque 400 servo in a TRX 4 or TRX 6 model. The Traxxas High Output BEC is the only battery eliminator circuit designed for a factory fit in Traxxas models, and ensures maximum performance when adding high power draw accessories to your model.