The silicon O-ring fitted between the end bell and stator helps to conduct inner heat to the unique motor case to maximize cooling for extreme cooling conditions. The built-in Hall sensor Non-Adjustable end bell combined with a high precision and balanced rotor guarantees the user a smooth and linear power on demand. Customized 3.5mm low impedance bullet connectors soldered to the motor wires guarantee "plug-and-play" and stable connections between the ESC and motor. The end bell is easy to be removed for maintenance purposes and for the replacement of common wearing parts such as rotor and sensor module (EX bearings). when pairing the Quicrun3650 G2 motor with the hobbwing quicrun-10bl60-sensored ESC, the excellent match between ESC and motor will give you a very smooth and linear power band.