Drop forged from carbon steel/chrome Vanadium steel,  hardened and tempered to sustain higher torques. Finally  machined Bi-hexagonal serrations are geometrically  perfect to reach faster for a uniform grip, to prevent  scratches and damage.  The Range SIZE (MM) AF/SAE WW 6 x 7  -- -- -- 1/4 x 5/16 -- 8 x 9  -- -- -- 5/16 x 3/8 -- 10 x 11 3/8 x 7/16 -- 12 x 13 7/16 x 1/2 -- 14 x 15 1/2 x 9/16 1/4 x 5/16 16 x 17 9/16 x 5/8 -- 18 x 19 5/8 x 3/4 -- 20 x 22 3/4 x 7/8 5/16 x 7/16 21 x 23 -- -- 24 x 27 15/16 x 1 -- -- -- 7/16 x 9/16 25 x 28 1 x 1-1/8 -- 27 x 32 -- --
Ring Spanners GT-104
GT-105