Folding Bike Lock
Different than your typical U-Lock or chain, the Foldylock (designed in Tel Aviv) opens up when in use and, when you’re riding, folds into a compact package that you can easily mount on your bike-frame or toss into a backpack. The lock is easy to transport, but doesn’t sacrifice security: six hardened steel links (coated in plastic to avoid scratches to the frame) stand up to bolt cutters, hack saws and more. Note that it’s a hefty 3.3 pounds.
Added: September 2015
This product is sold by Foldylock