ONGUARD 8001 Brute STD U-Lock, Black/Yellow, 4.37 x 7.96-Inch

This lock has good test reviews and should help deter a thief, especially if you combine with multiple other locks. No lock will ever stop a determined thief, but if you bike looks like too much bother, they will likely pass by and pick an easier target. The lock is very strong, has a good locking mechanism, and comes with a number of spare keys. The lock can be attached to the bike via a clamp fitting, but keep in mind this is quite a bulky lock and is quite heavy.I use this lock to secure my bike frame, and combine this with two other cheaper (but well reviewed in tests) 'D' locks that both secure my wheels to the frame, and secure the bike at additional points to a secure object or bike stand.So far my bike has not been tampered with. Even a brazen thief with an angle grinder will not want to spend more than a couple of minutes cutting off bike locks in public. If they want you bike, make them WORK for it!

I followed another reviewers advice and removed all the plastic casing, makes it easier to fit in my frame bag and just easier full stop.Locks at both ends, thick shackle, long enough to lock frame and wheel.Considering most gold u locks are around £50 this is a well priced quality product

Good solid lock at a decent price.