Robust and Durable - Lock made of high-quality zinc alloy and ABS, robust and durable with a high degree of anti-theft, anti-break, and anti-cut function. The material of the hamburger lock is zinc alloy and special ABS material, which has the function of anti-theft, anti-cutting, tampering. Anti-theft and Waterproof Design - The surface of the lock core is fully sprayed with rubber paint, and the shock-absorbing bumper during transport reduces noise, effectively prevents damage to the bicycle frame, and can be locked directly onto the lock frame, protecting the folding lock and preventing the lock from locking. High-Quality Stainless Steel Key - 3 high-quality stainless steel keys with a distinct key mouth design to avoid mixing. There are also serial numbers, if the key is lost, it can be remade. High Security - Bicycles are usually quick-release seats, there are safety risks, can be easily removed. Wheel and seat distance of 23 cm or less, can lock the wheel and seat. After folding, the bicycle lock size is 5 cm * 7 cm, compact, lightweight, and convenient to store in a top tube bag, saddlebag, etc. Easy to Carry, Compact and Flexible - The folding lock fits most bicycles, it weighs only 575g and is easy to carry with special rivets that make it easy to fold.