New Motor Smart Robot Car Chassis Kit Speed Encoder Battery Box For Arduino Features: 100% Brand New. Intelligent car chassis Tracing car Robot car chassis with code disk Ideal for DIY Mechanical structure is simple, it is easy to install. This car is the tachometer encoder With a 4 AA battery box and power switch. (Batteries not included.) Can be used for distance measurement, velocity. Can use with other devices to realize function of tracing, obstacle avoidance, distance testing, speed testing, wireless remote control. Size: approx. 20 x 14cm(L x W); Wheel Size:6.5cm (Dia.) x 2.7cm (H) Note: motor power supply is 3V~6V. All the parameter above is tested without load. Package Content: 1 x Car Chassis 2 x Gear Motor 2 x Car Tire 2 x Speed Encoder 2 x Fastener 1 x Universal Wheel 1 x Screwdriver All Necessary Screw And Nut