When it comes to locking your bike securely, a U-lock is pretty much the best way to go. The things are heavy, though, plus their rigid shackles can't be bent to pass around thick poles or other obstacles. That's where the Litelok Flexi-U Silver is designed to come in.
Like its predecessor, now being called the Litelok Gold, the Flexi-U incorporates a hardened aerospace-grade steel lock casing, along with a shackle-like strap made of a patented material known as Boaflexicore.
The latter consists of layers of high-tensile steel strands and a proprietary polymer composite. What results is a strap that is lightweight and flexible, yet reportedly still very resistant to damage by tools such as bolt cutters or hack saws.
One of the main things that sets the Flexi-U apart from the Gold is the fact that instead of its strap being completely circular in shape, it's U-shaped like the shackle of a U-lock. This feature makes it better suited to locking the frame and wheel of a bike to a nearby immovable object, such as a sign post.
The Flexi-U's strap is also lighter and more flexible than the Gold's, although this is due to the fact that it's narrower, and thus doesn't offer quite the same amount of security. British lock-testing organization Sold Secure thus gave the Flexi-U Silver a (still pretty good) Silver rating instead of a Gold, hence the lock's full name.
Additionally, we're told that the Flexi-U incorporates a new vertically-aligned locking mechanism, which is easier to operate than that of the Gold.
The Litelok Flexi-U Silver is available now in Regular and Large sizes, weighing a claimed 640 and 730 g (1.4 and 1.6 lb) respectively. They're priced at US$100 and $120, and can be ordered via the link below.
Source: Litelok
Maybe better than a cheap cable lock but not by any means high security.
If you value your bike, you should use 2 locks anyway. A U and another. I would go for a different type too so why not a Litelok. They have the advantage of being very light. If you're just tying up your bike to a post the time to have a coffee or a beer, it's ideal. If you're leaving it overnight somewhere then you will need 2 locks anyway and a different mindset. These locks are far better than the cheaper coiled ones whatever the video shows.