Can be transformed into a Self Defense Brass Knuckles very easily, unique creative design! Stone Wash Finish One Finger Knuck, Two Finger Knuckles, Full Finger Knuckles, multi-purpose It can pass airport security check easily. Full 304 Stainless Steel Made, no rusting, and very durable. CNC processing, hand polishing, the surface is very shining and smooth. Only 110g, very light. Inner diameter is 22mm, approx Size 13. Special attention before purchase.