[compact, durable and robust] the bicycle chain has folded dimensions of 120 x 60 x 45 mm and is very small, but weighs 735 g with the bracket. PA6 plastic lock body + high tensile steel alloy (10 x 15 mm) and zinc alloy + copper alloy with ABS cover, giving it a combination of resistance to cutting, sawing and corrosion. [Four-Digit Code Combo] 4-digit bike Chain Lock combo protects your bike and makes it safer and more convenient for you to set your password. The encoder wheel rotates smoothly and a "click" is heard with each rotation. To reset the Lock Code, simply press the black button to the desired depth. [Flexible Folding Design] Advanced self-rotating rivet technology is used to reduce the gap between joints and hold them tight. 8-joint foldable 360 degree swivel design makes folding easy and flexible. Dimensions folded: 12 x 6 x 4.5 cm, extended dimensions: 30 x 30 cm, support for multiple bikes. [Compact and easy to install] Adjustable diameter bicycle lock bracket for different seat tube sizes, easy to use. The portable design makes the bike lock compact and firmly attached to the bike stem. Stable, safe and impact resistant. [Reflector on the bracket] At night, the driver is more easily noticed by the car behind him. The bicycle safety chain lock bracket ensures the safety of the rider. Not only protects your bike, but also helps keep you safe when riding at night.