Rings made of forged and mechanized steel.
QR mounts are quick to mount and dismount. The lever is rotated forward and a cam on the shaft of the lever engages the base of the ring, pulling it down and forward on the base, solidly locking it in its "zero" position.
NOTE: Do not tighten the wing nuts of the QR mounts too much. With the hand it is enough (with the fingers). A tighter closure does not mean a more precise fit.
Measures:
1. - 30mm. EITHER
2. - 4.588mm.
3. - 19.558mm.