These are two brackets that can mount to the bottom of the Trekker to hold photo reflectors. Black and white contrast disks are included that can be read by sensors to allow the microcontroller calculate how far the robot has traveled.
This is a MLT-JR tracked robot platform and is equipped with 32mm motors, a motor controller, and Spektrum remote control. This is a rugged treaded robot platform. The robot handles up to 15lbs of additional payload and travels up to 220 feet per minute.