These silvalume hooks have the broadest range within the Susan bates family of hook. Made of lightweight aluminum, each silvalume hook undergoes a special anodizing process that etches away all surface impurities. In addition, each hook is heat treated for strength and durability and polished for a velvety smooth finish. Each size is color coded so you can find the size you need at a glance. These hooks famous in line head helps reduce wrist motion for fatigue free crocheting and helps you maintain a more consistent gauge. This set includes hooks in sizes 4 mm, 5 mm and 6 mm.