I use one of these: http://lockitt.com/Lockitt/product/CHPS1312.html
. From the website: Protector 1/2" - 13mm hardened boron steel Protector chain in 3.3ft - 1.0m length, made in the UK.
Sold Secure Motorcycle Silver / Bicycle Gold standard approved by Great Britain's independent Sold Secure testing house.
Highly resistant against standard and readily available bolt-cutters. It will take a massive monster cutter and a huge person to cut this chain by hand.
Protector 13mm is much lighter than its 16 and 19mm bigger siblings. Still one of the highest-approved chains in its class, made from high grade European raw material and put through a specific hardening process to become hard enough to resist cutters and saws yet flexible enough to withstand freeze and prying methods.
- See more at: http://lockitt.com/Lockitt/product/C....ajMY9fSa.dpuf
Secure with one of these: http://lockitt.com/Lockitt/product/DLAB8077.html
Yah its expensive. But so is my Honda EU3000is. The chain is remarkably tough and would require a great deal of manipulation to work through. Which is where the screaming disk lock comes in.