Heavy duty concave trimming knife blades to fit all types of Stanley, Stanley FatMax, Dolphin, Allegro, Shark and other makes of hand tool. Used by professionals in industry, flooring, roofing, warehousing, subcontract packing, DIY, crafts, graphic arts and for many other uses. They are stamped 'Heavy Duty', 'Made in Sheffield'. Manufactured in hardened and tempered carbon steel, these razor sharp heavy duty quality blades are designed to withstand the most arduous materials and tasks. The blades are lightly oiled and are packed in cellophane wraps of 5 pieces.