Rugged and durable security: The folding bicycle lock uses 26 alloy structural steel chain links, providing strong and durable protection with a 12level antitheft rating and fatigue strength. It is designed to resist breaking and cutting. Surface treatment and frame protection: The chain is fully coated with rubber paint to effectively prevent rust, oxidation, and corrosion, while also safeguarding the bicycle frame from damage. It can be locked directly onto the lock frame. Portable and compatible: The lock mounting bracket fits almost all bicycles, and the folding lock can be easily placed on the bracket for convenient transport. It weighs 1.26 pounds and is palmsized for easy handling. Secure key cylinder: Features a unique circular keyhole and key design for enhanced security, with 3 stainless steel keys. The lock cylinder has layered protection, making it stronger than ordinary lock cylinders. Practical use scenarios: Quick city stops: Lock your bike to a rack or post during short errands, using the bracket to keep the lock readily accessible. Daily commuting and campus use: Its compact size and bracket compatibility make it ideal for everyday rides and securing your bike on campus or at work. Longer stops or travel: The robust chain and secure cylinder provide reliable protection when you need to leave your bike unattended for extended periods at transit hubs, shopping areas, or hotels.