9mm steel chain links in a 120cm chain. One end is a ring noose, the other end plugs into your wheel lock! Adds extra security for your wheel lock - also very helpful for locking a partner's or child's bike to your bike.

NOTE: Only works with a wheel lock! 

Kryptonite 912 is compatitble with Kryptonite wheel locks. AXA ULC is compatible with AXA wheel locks.