Option Lock is accessible from either side
If you routinely park your bike in cramped areas such as a multi-bike racks, then there may be times when you find your lock rather difficult to access upon leaving. It was with this in mind that LA-based cyclist Scott Gold created the "two-faced" Option Lock.
Unlike a traditional U-lock, the Option Lock takes the form of a rectangle when in use. It consists of two steel crossbars – each one containing its own keyhole and cylindrical locking mechanism – joined together by two solid steel shackles. All of the components are rubber-coated, to keep them from scratching the bike's paint.
With an eye towards saving space in backpacks or the included bike-mounted carrying case, the lock can be kept disassembled while in transit, with its four pieces sitting side-by-side instead of assembled into a rectangle.
It's put together around the bike's frame and an adjacent immovable object when locking up, and when it's time to leave, the user simply unlocks whichever crossbar is easiest to reach.
If you're interested, the Option Lock is currently the subject of a Kickstarter campaign. A pledge of US$55 will get you one, when and if it reaches production. The planned retail price is $65.