... alloy,Brass,Carbon Steel,Stainless Steel.1.1.2 Lock Cylinder: Zinc-alloy,Brass, Stainless Steel.1.1.3 ... the service life of the lock, The hardness of the lock house and cylinder pin have over HRC55 after ... could prevent the destructive action to the lock cylinder by tools such as drills.4. Features of ... 2000.4.3 Trouble-free and long service life. Waterproof, dustproof, anti-blocked cylinder, durable ...