26S-610 for 1936M wrenches from 6 x 7 to 16 mm x 17 mm.26S-1216 for 1936M wrenches from 17 x 19 to 24 mm x 27 mm.26S-16 for 1936M wrenches from 25 x 28 to 46 mm x 50 mm.Chrome plated micro-matte finishing provides high quality surface.High-performance alloy steel