DIY 2WD Smart Car Robot Chassis Kit Arduino MCU with speed encoder

This car has the tachometer encoder- speed encoder 1:48With a 4 AA battery box and power switch (batteries not included)Can be used for distance measurement- velocityCan use with other devices to realize function of tracing- obstacle avoidance- distance testing- speed testing- wireless remote controlSize: 20 x 14cm (L x W)Wheel size: 6.5 x 2.7cm (Dia. x H)Instruction Assembly - Not includedPackage included:1 x Car chassis2 x Gear motor2 x Car tire2 x Speed encoder2 x Fastener1 x Universal wheel1 x Battery box(batteries not included)All necessary screw and nut