The optimized 4 digit combination, making 10,000 password combinations available to set your own. It is 10 times harder to crack than a 3 digit. The big codes make it easy to read. The unique side window design helps easy aligning. And the lock is equipped with an advanced damper device inside the wheels, making each dialing click into place with better accuracy, while it also brings appropriate hindrance to stop the wheels to move randomly as we do not want. Sturdy zinc alloy body and hardened steel shackle offer extra resistance to cutting and sawing. Waterproof and anti-rust, they are designed to be the most reliable dial locks for you.