This is a servo motor folder. This is a Tower-pro SG90 made only. SG90 is inexpensive small servo motor. About $ 3. SG90 is a friend of 9g servo. All of the size I am aligned with the 50mm. This part is <2>mm thick. In addition, there is also a <3>mm thickness specification. Small gripper is located in the 3mm version. http://www.thingiverse.com/thing:746116 I can be mounted at an angle of 90 degrees. I can be mounted to the arm part. I will connect the servo in M2 × 8mm bolts and nuts. I will connect each part in M2 × 8mm bolts and nuts.