The Blue Tang HYDRALLOY is UK’s improved take on the classic, multi-functional dive knife. We patented our own HYDRALLOY steel for a blade that is both strong and corrosion resistant where most competitors’ blades only offer one of those features. The Blue Tang HYDRALLOY knife is built rugged, with a serrated edge and a hooked edge for cutting through all types of rope and line. It is the ultimate safety tool.