When I bought my bike 5 years ago, I bought all the accessories to go with it, the lights, bell, pump, bike lock etc. I left no stone unturned with what I needed to buy, I was uber efficient and most of the items I bought have been used, well at least once anyway.
Where I live, a bike lock is an essential piece of kit when owning a bike, I once had my Hoover stolen while I was propping my door open with it to help the removal men when bringing in a new sofa!! I bought the Abus model of bike lock as it looked sturdy and thick enough to withstand attempts to cut through it. The flexible cable is 14mm thick and isn't horrendously heavy either. It is a spiral shape and has a lock mechanism at one end that you need the key to unlock. Abus is a shortened version of August Bremicker und Sohne who started making padlocks in 1924.
I paid £12.99 for this from Halfords roughly 5 years ago and didnt think that was too expensive, my bike cost more than that and I would rather pay that little bit more to guarantee the security of my bike, than have to pay for another bike. This came in a plastic wrapping that was almost impossible to get into. I had to use scissors, welding torch etc just to get into it, nightmare. I believe now these just with just a cardboard sleeve attached over the coil, much easier!! The cardboard packaging shows the security level of the lock as well. There is a Level System that goes from 0 to 15 and each lock is measured on a scale of how secure it is, this lock comes in as a 7 which is half way, that's good enough for me.
The lock came with two keys on a ring; I very soon lost one of the keys so am down to one now. I have this coiled round the saddle pole of my bike and having it there it doesn't get in the way while I am riding. This bike lock is 150cm long which I have found to be plenty long enough to wrap round, fences, trees etc. I have also managed to chain up two adult bikes and my sons BMX with my lock so it does stretch quite a long way. The keys are easy to insert and turn in the lock, also when doing the lock up, you just have to push one side into the other until it clicks and the self locking mechanism firmly holds it in place.
I would highly recommend this lock as I have tried other thinner ones, although the actual coil itself stood the test of time, the keys did not. I have had two keys break in the key hole of the lock, luckily it was while I was trying to remove them from my bike rather than from round a tree or fence. This may have something to do with the fact that I leave them on the bike and my bike is kept outside, I should probably remove the lock from the bike and store it inside rather than letting it be battered by the elements. The Abus lock however has not had this problem and fingers crossed is still going strong.
Abus Blaster 850 Coil Cable Lock. Locks. The Abus Blaster 850 Coil Cable Lock respresents incredible value for money. The robust Blaster combines the 14mm thick cable of the Millennio Phantom with an extremely rugged lock body. Technology: Strong ....