These 400w V3 motors are working perfectly with smooth speed and brake control, special programmed for Backfire G2 black and G2 galaxy since 2020; and ERA 1st generaiton electric skateboards.  Power system: They fit Backfire G2 Black and Galaxy 2020 and ERA (1st generation only, does NOT fit ERA 2 or ERA 3), working under the10s2p power system with 36v to 42v input.  Connectors: 9 Pin or MR30 The V2 MR30 motor only fits the G2 Black before June 2020.  Since June 2020, we updated all MR30 plug to 9 pin plugs for Motors and Esc as Version 3, please select the correct option for your board. Feel free to check with our tech support if you are not sure to avoid ordering wrong parts.   The Back motor set includes: 1 Back Truck set Two 400w motors with back wheel sleeves installed The single motor without sleeve includes: 1 single motor without sleeve or screws The Single Motor Set includes: 1 single motor, bolts, motor cap, and sleeve.