Sturdy lock core, durable, pure copper key, smooth opening. Thickened and bold bolts, solid bolts resist impact and are more durable. Thicker material, thicker zinc alloy, thicker bottom plate makes the lock body stronger. Zinc alloy lock body pipe, choose thicker zinc alloy pipe with higher copper content. Installation environment, suitable for casement doors, side-by-side doors, glass doors, shopping mall doors, etc.