Heavy duty tactical scope ring set of solid heat-treated aluminum alloy for military and law enforcement uses. Fits Picatinny 1913 rails. Works with 30 mm tube scope or 1inch tube scope using included size inserts. 1 1/2inch (38mm) center height good for scope with objective size up to 56mm. See-thru design allows use of regular iron sights with scope mounted. Large clamping nut for secure mounting. This ring set is for the serious shooter that wants the best in strength and ruggedness. Anodized black matte finish. TWO rings in the set with Allen wrench included.