SECURE & RESETTABLE: 5-digit resettable combination bike chain lock, much safer than other 4 digit locks. Easy to set your own personalized number combination. STURDY & DURABLE: It's hard to break through as the lock cylinder of the bike lock is made of zinc alloy. The bicycle chain lock is made of 0.16 inch alloy steel which is drill-resistant and anti-tech unlocking..Safety tip: Please do not leave your bike out of your sight for too long, especially in high crime areas, no bike lock is 100% safe. SCRATCH-PROOF FABRIC PROTECTION: The bicycle chain lock is wrapped by a high quality polypropylene fabric, which is scratch-proof and wear-resistant, anti-hot and anti-icing hands; it protects the chain and prevents it scratching your bicycle frame, long lifespan. CONVENIENT TO USE: Combination locking mechanism provide keyless convenience and set your own password by easy steps.