Designed to fit Mil-Std. 1913 scope bases, Nightforce rings are precisely manufactured to match the machined recess of a Nightforce Mil-Std. 1913 base, providing perfect alignment and accuracy. Nightforce rings are designed and produced in-house to exacting specifications entirely out of steel or from 7075-T6 aluminum with beta series titanium crossbolts and jaws. All Nightforce rings are 100% micro-radiused and honed in pairs for perfect fit of 30mm scope tubes to prevent the possibility of the rings damaging your scope.
Sinclair, Issue:4B, Page:209
Ring heights are measured from the top of the base to the center of the ring.