As someone who lives life on two-wheels, testing bike gear isn’t just a fun hobby – it’s part of my daily life. E-bikes are how I get around and the gear I use with them helps me avoid needing to use a car. And so when I find something new that I incorporate into my everyday kit, that means that it has proven itself as both effective and worth it in the long haul. The latest lock that I trust to use on my own electric bikes is the Foldylock Forever from Seatylock.

Locks for e-bikes can be a touchy subject. We’re talking about expensive transportation machines, and everyone seems to think they know the best lock that is better than anyone else’s. Then, someone inevitably will tell you why that one pales in comparison. Someone will eventually mention Lockpicking Lawyer and say you’re all wasting your time. Basically, there’s little consensus.

But as someone who both rides e-bikes as a daily form of transportation and also has a mechanical engineering degree tucked away in his back pocket for occasional use, hopefully I can shed a little more light on the subject.

I’ve been testing the FoldyLock Forever for several months now, and compared to the literally dozens of e-bike locks I’ve tested, this has become my new favorite model. It’s not cheap – I’ll tell you that immediately. At $125 on Amazon, this sucker is expensive. But good quality isn’t cheap, and if I could go back and spend that $125 before my $3,000 e-bike was stolen last year, I’d do it in a heartbeat.

There are a few reasons I’ve fallen in love with the Foldylock Forever. First of all, folding locks are much more convenient than chains because they provide high-security in a much more manageable package. I still recommend using more than one lock of different styles at the same time, but now the Foldylock Forever is definitely the first lock I grab.

The lock folds up to fit in your hand or and can be securely mounted in a smaller area of your bike with the included holster, yet it still gives you the adaptability of a chain to lock around or through weird-shaped objects like trees, quirky bike racks, etc. Compared to high-security chain locks that can weigh 11-15 lb (4.9-6.8 kg), the Foldylock Forever weighs just 3.9 lb (1.8 kg). There are simply fewer links that need to be beefed up to reach that level of security compared to a chain lock.

The holster is ultra-convenient to use because there are no additional straps or fasteners – the molded shape securely holds the lock without rattling and you simply slide it out when you’re ready to use it.

Folding locks are also largely impervious to leverage attacks (like when thieves put a car jack in a U-lock). Cheaper folding locks can still be vulnerable to bolt cutters or nut splitters, but the Foldylock is hardened against both attacks. The hardened steel links defeat bolt cutters and use high-security rivets with such high precision that you can’t get a nut splitter in there.

When Foldylock claims that this is the most secure folding lock in the world, that isn’t marketing speak or hyperbole. It’s been tested and certified as such. It not only gets their own highest security rating, but it is Gold-Certified by Sold Secure, an independent, UK-based non-profit organization that tests and certifies locks based on how hard it is for them to be defeated by various attacks.

It’s not the only folding lock to reach this high level of certification from Sold Secure, but the lock is currently undergoing testing from other international lock-certification agencies that have never been achieved by folding locks.

Compared to other folding locks on the market, many of which I’ve tested, the Foldylock Forever is also much quieter and easier to use. Others have more play in their joints and a jingle-jangle sound similar to chains. Many have a limited 90-degree swing at the locking point, meaning it can’t really open all the way like a straight link. But the Foldylock Forever’s extremely high tolerances mean there’s no noise and the locking point can spin all the way around, effectively making it into a full circle (or rather, hexagon) that doesn’t limit your ability to lock around weird-shaped objects.

You don’t have to take my word for it – just look at the reviews. On Amazon, it has a 4.6 out of 5 rating, which is basically unheard of in the lock category. Part of that is because locks just aren’t a sexy product. When they work well, people don’t think about it. But when they don’t work well, people run to Amazon to complain about it in a bad review. That means keeping review numbers high on products like these is a feat in and of itself.

I won’t spend too long on this last issue, but just to address the “what about thieves that pick the lock?” argument that inevitably comes up from pedants, that’s basically a red herring. Most bike thieves, even the professionals, come prepared to break a lock, not pick it. And if someone truly is skilled enough to pick these types of cylinders (think “Lockingpick Lawyer” level professional), then the bike is already theirs. A good lockpicker is the same thing as having the key. There’s nothing you can do about it. Sure, the cylinder on the Foldylock Forever has higher security than a cheap bike lock. But nothing stops a truly professional lock picker because they effectively have a key to everything.

I’ve tested a lot of locks, but I’ve never found one that is as secure, lightweight, and convenient all at the same time. It’s not cheap at $125, but for an electric bike that is also not cheap to replace, investing in a solid lock is critical, in my opinion. I’ve been using the Foldylock Forever on my own bike and my wife’s bike, meaning I trust my family’s gear to it.