This cool foldable bike lock is 34% lighter than the more well-known Foldylocks brand although Foldylocks advertises itself as the lightest lock. LED lights are tested to be rainproof during my rides.
The links are thick and heavy so a thief can't use bolt cutters to cut it (light you could with the compact cable locks.) Nothing is fullproof. It would take some more serious tools to quickly get through this thing.
I love the curved design, which I personally think that it provides a more useful shape giving you a little more maximum effective length for the number of links considering the lock will form an oval when you lock your bike. This is big enough to lock the bike to most nearby poles, trees, or other objects and could easily lock 2 bikes together probably 3.
The mount idea is just genius. The folding bike lock is very very secure by cinching the notched strap with a bolt using an allen wrench (provided). It locks into place. Just brilliant. I have a saddle bag so I could not mount it around the seat post facing back so you have a rear reflector.