Delivery by the seller was excellent - it arrived within 3 days. Order on Saturday and arrived on the Wednesday.
I've been wanting to install one on my commuter/utility bike, but it wasnt until my wife bought her new dutch buke that I actually bought the twin pack - purely so that the four keys fit either lock and interchangeable. I've had these locks on bikes when I was a child so I knew the basics in its fitting to the bike. Go on Youtube and you will find videos on fixing these locks.
My main lock is an Abus Xplus chain lock which I attach and lock the front wheel and frame to a fixed object. The Abus 4850 locks the rear wheel as its permanently fixed. I also bought the Abus (12mm thick) cable that can be attached to the 4850 and run this through my brooks saddle and where possible to a fixed object. I've fitted the 4850 within the rear frame triangle of the bike. This way even if the bad guys were to remove the lock from the bike frame or even cut the cable, they would still not be able to remove the rear wheel as the Abus 4850 would still be locked to the wheel and unable to be passed through the rear fork.
Remember this lock should not be your main lock to your bike but could pass as your secondary locking system when used with a 10mm (preferably 12mm) thick cable leash or better yet security chain.