This is a Utility arm pocket that mounts to the Skin instead of the frame. This will make the utility arms line up perfectly and still be functional when combined with the servo mount piece, shaft and the printed Utility arm or modifiying your Resin or Aluminum Utility arm. You will also need a 1/4" D shaft like this one: https://www.servocity.com/0-250-1-4-stainless-steel-d-shafting with a total lenght of 1.75" or 2" with collars. You can add bearings for smoother rotation with an ID of 1/4" and an OD 0f 3/8" like these: https://www.servocity.com/0-250-id-x-0-375-od-flanged-ball-bearing