The tuning rings consist of 3 rings and some side parts to hang them up on a wooden or metal frame. One is the bearing ring (15mm thick), which makes it possible to flip backwards and forwards. The other two rings (available in 8, 10, 12 or 15mm) in which the shell is clamped, can be turned clockwise and counterclockwise. Some knobs make it possible to either make the rings turn or fix them in position.
The wooden or metal frame is not included.
Available in any size (standard size is 53cm, but I often make 50cm, 54cm or other requests)
Click here to see the manual and close-up pictures for assembly.