They use a pure carbon form in a elox machine that burns the shape into the metal Matzuo wasn't on the scene when Do-it started making molds the sickles are a little taller than mustads it would be rather costly to have a mold for every leg length but They could change their shape and put a slot instead of a dimple Maybe their gettin Money from Mustad for the fact their hooks fit exactly personally there inconsistent on weight until you set up to their 1/80 and out but then again their $100.00 bucks plus .