... punched into shape, anti-shock, anti-break,firm and reliable.l Multiple cross shafts, multiple safety: Adopt solid core square steel ... lock is drill-proof, smash-proof and technically open-proof.l Noiseless nylon roller: Specially high-hardness noiseless nylon roller, ... test Over 1010(1850F) in an airtight gas furnace for 1 hourl Multiple technical patents: Professional design, fine elegance, perfect ...