Description: Scope of application: car assembly upgrade. Easy to install, easy to use. Mechanical structure is simple, it is easy to install. The most economical and newest robot car kit with simple mechanical structure, a nice system and very easy to install. Smart car chassis tracing car robot car chassis with code disk, Ideal for DIY. Can use with other devices to realize function of tracing, obstacle avoidance, distance testing, speed testing, wireless remote control. Intelligent car chassis Tracing car Robot car chassis with code disk.This Mini Electric Motor is a general purpose motor, work with batteries or solar cells perfectly. Specification: Material: Metal Size: Wheel: outer diameter 85mm/3.35inch, width 31mm/1.22inch, inner diameter hex-to-edge distance 12mm/0.47mm. Package Includes: 1 Piece Trolley Wheel 1 Piece Motor 1 Piece L-bracket 1 Piece Brass Coupling Several Power Cords Several Screw Fittings