Durable 90 cm High-Performance Hardened Steel Chain Lock with Keyless 5-Digit Combination - Robust construction and anti-theft features: A high-performance hardened steel chain with anti-drill and anti-saw protection. The 90 cm total chain length provides strong security for bicycles, and these chains can be connected to other chains to extend the locking system as needed. - Sturdy lock cylinder and head: The locking head is made from high-temperature resistant ABS environmental protection material. The zinc alloy lock cylinder uses an international standard lock plug system and is dustproof, waterproof, and resistant to drilling and sawing. - Easy to use and portable: The dials move smoothly and precisely. The numbers are large and clearly visible even in poor light. When not in use, the lock can be wrapped around the frame or the handlebars for convenient transport and storage. - Keyless convenience with strong security: The advanced 5-digit combination provides over 100,000 possible combinations, reducing the risk of unauthorized access. Use scenarios - Urban bike parking: Secure your bicycle to a rack, post, or other fixed object in schools, offices, or city locations by wrapping the chain around the frame and the object. - Public areas and trails: Deter theft when leaving your bike unattended at trailheads, parks, or popular cycling spots by locking the frame and wheel together. - Travel and commuting: Carry and secure your bike or gear while on the move; wrap the chain around the frame or handlebars when not riding.