1. 1000mm length with 6mm square chain links, which is made of hardened steel
 

2. The chain is made of special hardened steel with heat treatment
 

3. The lock cylinder with advanced Switzerland technology, only 0.3-0.6mm thickness key, well protect against technical stealing.
 

4.  The lock sleeve is luminous when meet the light in the darkness, makes riding safe in the night
 

5. Code design, avoid losing the keys