These 19mm Dovetail Scope Rings are measured at the top/ widest portion of the dovetail.
These are commonly used on old Double Square bridge rifles such as the Heym or BRNO.
This will not work If you are looking for a 19mm dovetail set up for CZ 550, or CZ 557 with the recoil lug on the rear mount
Height: .410″ in 1″; .500″ in 30mm.