This is a very small light sensor. A photo resistor (also known as a photodector, or photocell) changes resistance depending on the amount of light it is exposed to.
This is an SST tracked robot platform equipped with 32-millimeter motors, a motor controller and a tethered remote. It has a pan/tilt camera with high power LED lights. This is a rugged treaded robot platform.
Use these roll pins to fix sprockets to a shaft and keep them locked in place.