This HiTec servo is a multi-turn servo winch. Depending on the RC system used, you can get up to 4 full 360 degree revolutions of high torque out of this servo.
For a general servo overview manual follow this link.
These are HiTec HS-645MG Ultra Torque Metal Gear Servos for your Heavy Duty needs!
These are HiTec HS-422 Servos for use in any application.
1/4" Hex Size, 2" Length, 4-40 Thread Size
This is a small tracked robot equipped with 42mm motors, a motor controller, and Spektrum remote control. This is a customized prebuilt version of TP-230-042 with added track brackets.