To date, our experience with bike locks is not a very positive one: while they’re absolutely necessary in our part of town, durable chains and U-locks are usually too big and heavy to easily carry on our bikes, and coils are worse, proving hard to tame. Foldylock solves both these problems thanks to a clever design that packs tight for transport and unfolds into a 35.5-inch “chain” to secure your bicycle to a post or bike rack. Made of six fiberglass-reinforced hardened steel links, Foldylock stands up to would-be thieves thanks to drill-resistant VSR rivets and a reinforced steel housing around the lock cylinder, weighs roughly 3.3 pounds, and rigs up to your bike rattle-free thanks to an included case.

Pick one up at Amazon – $95