black alloy one piece cantilever Vector Optics scope ring with anti-cant. Has see through design (with anti-cant removed). Suitable for any centrefire guns and .22 guns and airguns with a 20mm weaver / picatinny rail. fits 30mm scope tube and 1" scope tube with provided spacers. 1) light 156g 6 screws per ring. flat top and picatinny top. 40mm base to centre. 55mm between rings. 138mm overall length. 2) heavy 185g. 4 screws per ring. flat top. 40mm base to centre. 59mm between rings. 149mm overall length. New but not in original packaging.