【HIGH-PERFORMANCE SECURITY】Enjoy complete peace of mind with this high-strength U-lock, featuring a robust 16.5 mm diameter shackle. Its hydraulic shear protection and fire-resistant design, combined with a 2.5 mm silicone sleeve, effectively protect your glass doors from scratches while maintaining the lock's integrity. 【4-POSITION ADJUSTABLE RING】Thanks to its precise adjustment mechanism, the U-shaped shackle adapts to 4 different inner diameters (120–150 mm), offering exceptional versatility for both indoor and outdoor use: glass doors, gates, sheds, fences, bicycles, e-scooters, and motorcycles. 【ENHANCED ANTI-INTRUSION】This 4-digit combination lock generates up to 10,000 unique codes – much safer than a 3-digit model. You can easily customize your code for reliable protection of your belongings and privacy. 【DURABLE AND WEATHER-RESISTANT MATERIALS】Made of zinc alloy and hardened steel, it is resistant to water, impacts, and cutting attempts. Its complex serpentine channel locking mechanism significantly improves resistance to picking and unauthorized tampering. 【PORTABLE AND MULTIFUNCTIONAL DESIGN】With a total length of 22 cm, this U-lock fits easily on most standard locks. Ideal for securing glass doors, exterior gates, garden sheds, fences, bicycles, scooters, and motorcycles – wherever reliable and practical security is required.