1 PIECE FULLY ADJUSTABLE - Adjustable for windage, elevation, height and lateral position for perfect dovetail centering. Can suit upto 60mm lens dia. Arrestor pin included. 1 Piece Mount. Base Fitting: 9.5 - 11.5mm (38") Dovetails - Most popular size (suits most modern airguns & .22 rimfire rifles). Tube Size: To fit 30mm diameter body tube scopes. Front Lens Size: Up to 60mm - This figure describes the maximum size of the objective (front) lens the mount is designed for when the dovetails are flush with the barrel. Please bear in mind scopes with front PX adjustment will often need higher mounts. Bolt Type: Allen Key bolts - Allen Key(s) Supplied. Clamp Design: Double Clamp (four bolts on each cap). Dimension A: 25mm - 27.5mm Dimension B: 110mm