This Wheeler 30 mm High Picatinny mount is meant for use on Weaver/Picatinny rails. The clamping bolt will double as a stop pin to prevent displacement by recoil.
Made of high quality aluminium, de Wheeler 30 mm High Picatinny mount is lightweight and because the flanges are diagonally orientated, they could be kept small while still retaining six torx bolts for sufficient clamping. This, in effect, made it possible to mount a foldable level.
The level is a handy addition to help you keep the reticle and with that the rifle perfectly level, which is, especially at longer distances, very important to maintain accuracy.