Turtle Rover – Manipulator Arm 20.07.201820.07.2018 Michael Manipulator main servos. Finger assembly. Finger mechanism. Fingers, spacer and clips are 3D printed at Shapeways. Getting these tiny screws inside the fingers requires a trimmed off Allen wrench. In most extended position the arm is able to lift and hold a 500ml water bottle. But depends on servos, though.