Underwater Kinetics Blue Tang Hydralloy Drop Point YellowThe Blue Tang HYDRALLOY is UKs 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.