Pri's one piece cantilevered 30mm Low ring set. This base and ring set allow the shooter extended eye releive in a one piece base. This also allows the shooter to remove and install scopes quicker then the standard set of rings. The base is constructed of hard coated black oxide aluminum. Is installed with self locking thumb screws but is available with locking nuts. The overall length is 6.375" Center line of scope to receiver height is 1.3" ring to ring is 3.15".