Shop name:Chong Qing Shuo Yue Ke Ji You Xian Gong Si 550 Brushed Waterproof Motor is a budget motor built for messy, dirty, off road action. This 550 motor has a 30% armature than a standard 540 size motor for extreme monster . Heat-resistant motor with built-in cooling fan, allows fast speeds, long runtime, and long lifetime. High strength magnets maximum performance. 1/8th inch shaft diameter,ball on output side. plugs is easy connection with no soldering needed. Type: 21T Motor Diameter: 36mm Motor Shaft Length: 11mm Shaft Diameter: 3.17mm Use voltage: 7.4-11.1V(21T) Weight: about 230g Suit For: RC Car / Boat Remarks: "T" mean the number of turns. 12T and 21T motors fit high speed RC Car. 29T 35T motors fit RC Crawler. Tool Supplies:Assembly Category RC Parts & Accs:Servo Accessories Use:Vehicles & Remote Control Toys Technical parameters:Value 2 Remote Control Peripherals/Devices:Receivers For Vehicle Type: Four-wheel Drive :Assemblage Wheelbase:Screws color:As shown Material:Metal Package Contents: 1 x 550 Brushed Motor Only the above package content, other are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.