This is a set of medium height scope rings made specially for use with high power airguns. Can mount scopes with objective size up to 40mm. Side clamping plate can be reversed so that the rings work on both 3/8inch and 11mm dovetails. One of the rings has a threaded stop pin built in and can be applied when needed using the L hex wrench that comes with the ring set. Two clamping screws on each ring for the max. holding power