I purchased the combination ziplock. I locked my bike at my local train station cycle hub on returning I entered the combination code and the lock would not open despite numerous attempts. In the end i had to resort to forcing the lock with my bike tools (thank goodness I had them with me). After about 10mins I was able to disable the lock and retrieve my bike. Luckily I was able to prove to the police that the bike was mine as i had the keys for the other AXA locks I also use!