This patented ring design utilizes synthetic inserts that pivot within a steel outer ring allowing them to line up scope tube and rings without bending or stressing the scope tube. This assures no optical distortion. The rings come completely ready to go and can be used on any Weaver-Style base.
Big Book Catalog, Issue:69, Page:252
Sinclair, Issue:5B, Page:205
Heights measured from top of the base to underside of the scope tube.1"Med .270", High .420" 30mm Med .205", High .330", Extra High .582"