Features: Brand new and high quality. Mechanical structure is simple, it is easy to install. This car is the tachometer encoder. With a 4 AA battery box. 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. Gear Motor reduction radio: 1:48. Size: 22cm x 14.7cm, wheel size: 7cm x 7cm x 2.6cm. Note: motor power supply is 3V~6V. All the parameter above is tested without load. Package includes: 1 x Car Chassis 2 x Gear Motor(1:48) 2 x Car Tire 2 x Speed Encoder 2 x Fastener 1 x Universal Wheel 1 x Battery Box 1 x Power Button All Necessary Screw And Nut