• LONG LIFE: Black phosphate finish for long life • CHROME VANADIUM STEEL: For strength and corrosion resistance • ANSI: B18.3.2M-1979 ,GGG-K-275D • ANTI-CORROSION: Anti-corrosion treatment to enable low risk of rust • INCLUDES MOST COMMON SIZES: Most common sizes in one set for best accessibility • CONVENIENT PACKAGING: Hangable and visible • RING SET: All 10 sizes fixed together • SPRING FIXING: Easy to remove and to assemble