Bulldog STD U-Lock with 4 ft Cable – 13 mm Hardened Steel Shackle, 275 mm x 175 mm Frame, X2P Double Bolt Lock, Z-Cylinder Core, 5 Keys with LED for Secure Bike Protection

Superb lock. It’s very big kind of bulky, kinda heavy, but it will definitely make people think twice before trying to steal your bike using this.

Does it's job. Like the wide throat vs. the more narrow ones on the market. I own two of them and I think this is the one that comes with the nifty key with the built-in light.The only complaint. There is a plastic sleeve around the "U". It is not attached to the metal. Sometimes it will slide to one side and get low enough that the lock is difficult to lock up. Until I realized this was the problem, I got very frustrated with this.Last week, I got stuck in a bank of snow up in the mountains, no shovel and we used this, among other things, as a pick/shovel to dig us out. I'm sure OnGuard didn't intend that use, but just to let you know in a pinch this thing can do all sorts of stuff!

This is a very good product. While not the most secure of its kind, it appears solid and well built. The included cable has proved useful, especially for free-standing lockups during quick stops. Mounting clipdoes not impress and will not be used, but the lock lays nicely on the rear rack, secured by velcro straps.Overall a good buy and works well to protect my ebike. Comes with extra keys.

So far, this lock has done its job. I live in an area with moderate bike-crime and commute to an area with almost none. My garage is secure, but if I'm shopping near home, I want a big scary lock that'll make my bike seem significantly less attractive to a thief than the flimsy cable-locked bike next to me.This is that lock.At the end of the day, a bike thief with the right tools can break any lock and definitely any cable, unless you're willing to invest in and slug around professional grade steel chains. I'm not. I just want my bike to look less easy to steal and this lock does the trick.I have a strangely shaped bike, so it doesn't quite get around either of my tires and the frame, so I boot each tire to the frame with mini-u-locks, run the cable from this between them and onto this u, and secure this u to whatever I'm tying up to. There's an approximately 4" diameter water pipe at work that I lock to, and the round part of this lock fits around it no problem. The construction seems very secure and the insurance scheme, while a royal pain to fill out and send in, seems legitimate.My bike is my exclusive means of transportation, so I'm willing to make the investment to keep it secure!

This lock works great, and (so far) protects my bike even when locked up outside my building for hours all day or even overnight. My *only* complaint is that it tends to have a little rattle when biking and going over bumps, but that is pretty standard I think. I had trouble deciding between giving it 4 starts or 5, until I remembered how much better the mounting system for this lock is compared to other comparable locks. The mounting system for this lock is vastly more versatile, allowing my many different configurations that work on my different bikes (where as the mounting systems for other locks left me with no adequate options for a couple of my bikes, and I returned those to the store). I would definitely recommend this lock to others, and have now bought several to use on different bikes (at the same time).

my biggest concern when ordering a u lock was that it fit around my mountain bike frame and had a nice mounting bracket. this lock satisfies both of those conditions. I love the mounting bracket, easy to take the lock on and off and is very secure. the only small issue is that it makes a bit of a rattling noise as I ride over bumps, but my bike is pretty loud in the first place so not a huge issue. the lock seems pretty big and beefy, so nice and secure and fits fairly easily over my thick frame.UPDATE: about 4 months after purchase. changed from 5 stars to 2 stars.The mounting bracket has now completely broken after regular, almost daily usage. one part of it is very thin plastic and i could see it slowly starting to break only 2 months after purchase. the lock has also become extremely sticky, it is hard to turn and often times the key does not want to come out because it cannot turn all the way to the locked position, looks like some rust/corosion has gotten into the mechanism. sadly did not even survive one seattle winter. i am somewhat disappointed now.

Great Product. It's a bit bulky and the attachment to the bike is difficult, but other than that the lock is great and so far I haven't had any issues with the keys and the lock. I would definitely not recommend attaching it to the bike though, it's a bit uncomfortable. But then again, this might be because of my bike, not the lock.

I like this lock a lot. I had an old model that had some issues with the cylinder and while I was waiting for the company to send me a replacement, I ordered this one and have been really pleased with it. I especially like that the cable is fairly long and that the loops in the cable are big enough where one loop can pass through the other, making it easier to use the lock in varied situations.