These are considered Sub-miniature servos The servos are made by Hitec. On all Hitec servos the Black wire is 'ground', the Red wire (center wire) is 'power', and the yellow (third) wire is 'signal'. This servo has a Hitec/JR connector which mates directly with a 0.1" 3-pin header. This servo comes with servo arms.
These are HiTec HS-422 Servos for use in any application.
Use these roll pins to fix sprockets to a shaft and keep them locked in place.
This small synchronous switching step-down (or buck) regulator takes an input voltage of up to 38 V and efficiently reduces it to 5 V. The board measures only 0.7″ × 0.8″, but it allows a typical continuous output current of up to 5 A.