This gear kit contains 60 kinds of 0.5 modulus gear, the gear shaft 102A which there is copper gear, also the 2.3MM and 3.17MM gear included, some rack, worm and belt may you need too. Gears are made of ABS plastic and meets DIY requirements.
Use this module to measure the velocity of wheels or motors. With a light, laser or infrared emitter and receiver, this module would be help in DIY applications such as mobile robot.
Pololu Wheel for FEETECH FS90R/FT90R Micro Servo, 60×8mm Pair - Black
Super Micro 0.08sec/60degree 0.7kg.cm Analog Servo FS0403.