Star tracker for Beike BK-03 Ball Head, and M5 threaded rod. Short distance between tripod and camera,and no need for an extra hinge. I had to cut the arms in two, since my 3d printer is limited to 140x140x140mm. If someone wants to change or improve something, I can also upload the cad file. Parts list: 1 off - Beike BK-03 Ball Head with Quick Release Plate 1 off - Screw Adapter 1/4" to 3/8" 1 off - M5 Threaded rod 3 off - M5 Hex Nuts 1 off - Washer for M5