Now to tell the truth i did not buy this chain to lock up my bike, Bike chains and D locks are what they are just a visible deterrent something to slow down the thief and to stop people just walking off with your bike and in most cases they do a good job i guess but to a proper thief NO this chain would not last ten seconds it's too thin and so are the 8 and 10mm ones and the lock is weak too, You want a minimum of 16mm to 20mm in Diameter ( flat chain links ) so the links are wider and thicker than most bolt cutters jaws and i say MOST they'er industrial bolt cutters that have jaw sizes as large as 3/4 inch and are designed to cut hardened steel so do your research not only on chains and padlocks but also the thing's that are made to cut them and you'll keep you things maybe....because no matter how big the chain or how big the padlock if someone wants your bike and you leave it in a place where some one has say five ten min's with no one around and a pair of industrial bolt cutters you can say goodbye to your bike or whatever trust me. No I bought it has a carry legal weapon to defend my self from the usual cyclist haters, Arrogant old people who think because they are old the world owes them something including footpaths, walkways and the road...and of course the dog walker who ignores all signs and thinks they have the right to let their dog off the lead in parks and on public farmland etc too s..t and run where ever it may like including right under your front wheel and then say it was you who ran the dog over.:-) for that purpose i am sure it will work very well...unfortunately for some.