1. Material: stainless steel (square), cold rolled steel (round) 2. Scope of application: wooden doors, iron doors, windows, hotel doors, etc. 3. Made of stainless steel/cold rolled steel, waterproof and rustproof, beautiful and durable 4. Thickening and thickening, non-dislodging insurance clips, strong anti-theft performance 5. 3mm thickened chain, twisted welded tightly, not easy to break, anti-prying and tear-resistant, durable 6. The size of the window depends on the installation position, the greater the distance between the staggered, the smaller the window space 7. Simple installation, wide range of applications, suitable for a variety of scenes, but also your safe and comfortable living environment 8. Weight: square black about 74.1g, square silver about 68.2g, square red bronze about 72.5g, round gold about 58.2g, round bronze about 60g, round silver about 56g 9. Size: square about 8.55 x 3.9cm, round about 8.65 x 3.7cm, chain length about 18.7cm, hole diameter about 5mm