Compact, Heavy Duty and SturdyThe folded size of the bike chain is 4.72 x 2.36 x 1.77 inches, a very small size, But the weight with bracket is 735g. PA6 plastic+High-strength steel alloy lock body (0.39 x 0.59 inches ), and zinc alloy+copper alloylock cylinder with ABS cover, makes the bike lock combination anti-cutting, anti-sawing, anti-smashing. Passed 3.5M drop test and 5000N pull test. security chain lock make your bike safer Four-Digit Password Combine4-digit combination bike chain locks protect your bike to be safer, convenient for you to set your password. The code wheel is soft to rotate, each turn, you can hear click. Resetting the lock code takes a bit of effortto push the black button to the depth required, you never need to care about setting a password accidentally and dont know the new password. Remember your password, then start your riding without keys Sophisticated Design1. A good design of the bracket, makes the foldable bike lock firmly fixed on the bike tube, would never shake, no voice even riding on a bumpy road; 2. PA6 plastic covering protects your bike wont be scratched by the chain, alsoprotect the lock body away from rust and corrosion; 3. After entering the right code, you need to press the gray button to open the folding mountain bike lock, so it is more difficult for someone to open your bike lock without the password How to Reset a PasswordThe code wheel couldnt be turned when the lock is open. Password setting: Initial password is 0000, press black button and hold to set a new password along the groove, then release the button, remember your new password, finally,test if your new code could open the folding bicycle locks which are heavy duty anti theft Reflector on the bracket At night, the rider could be noticed much more easily by the car coming from behind. The bracket of bicycle security chain lock ensures the riders safety. Not only protects your bike but also helps you with your night ridingsafety.