550 Brushed Waterproof Motor is a budget motor built for messy, dirty, off road action. This powerful 550 motor has a 30% armature than a standard 550 size motor for extreme torque. 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 bearing on output side. Remarks: "T" mean the number of turns. 21T motors fit high speed RC Car plugs is easy connection with no soldering needed. 550 Motor Use voltage:7.4-11.1V Reduction Ratio:1:4.2 Motor Weight:about 230g Ratio Reducer Planetary Gearbox Weight:95g Type:21T Colour:As Shown Material:Metal Size: Motor Diameter:36mm Motor Shaft Length:11mm Motor Shaft Diameter:3.17mm Ratio Reducer Planetary Gearbox Overall Diameter:36mm Ratio Reducer Planetary Gearbox Total Length:43mm Ratio Reducer Planetary Gearbox Output Shaft OD:3.17mm Package Contents: 1 * RC Car 550 Motor 1 * RC Car Ratio Reducer Planetary Gearbox Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.