KEYSTONE RINGS
Contrary to the fact that both sides are in rectangular rings, they are rings obtained by arranging them in the form of a trapeze, not in parallel. The angle value is usually 6°, 15°, 20°. This trapezoidal design can be made on both sides and can be made double-sided as well as on single-sided keystone rings. Half keystone rings have no angles at the bottom edges and the ring is at right angles to the working surface.
Keystone Ring (T)
Half Keystone Ring (TT)
