Folding bike lock stays attached to the frame full-time
It can be a hassle, removing your bike lock from its frame mount (or from your bag) every time you want to use it. The Lobster Lock is different, though, in that it stays attached to your bike at all times – even when the lock is in use.
Made of heat-treated hardened steel, the Lobster Lock is permanently mounted on the bike's existing water bottle bosses, on the frame's down tube. A bottle cage can still be used, it just gets mounted through holes in the lock via two included long screws.
When not needed, the lock stays folded up into a compact rectangle. Once it's time to secure the bike, though, the lock's two arms are folded out to either side, run around the frame, an adjacent immovable object, and the front wheel, and then key-locked back together.
And while it is possible that a would-be thief could unscrew the lock from the frame, they still wouldn't be able steal it or the bike without some sawing and/or picking.
The locking and unlocking process is claimed to take just a few seconds.
If the bike has bottle bosses on the seat tube, the lock can also be mounted there and used on the rear wheel, leaving the front wheel to fend for itself. It tips the scales at a claimed 2.8 lb (1.3 kg).
The Lobster Lock is available now via the first link below, priced at US$74.99.