Kryptonite Keeper 712 Bike Chain Lock, 4 Feet Long Heavy Duty Anti-Theft Bicycle Chain Lock with Keys for Bike, Motorcycle, Scooter, Bicycle, Door, Gate, Fence,Black

Bought these for my brother to use for his electric bike when he goes to work, and so far so good. Heavy and sturdy and durable. Someone tried to cut it to steal his bike and the best they could do was a little mark in the outside cover. Couldn't get through the chain. So it has served it's purpose! Will continue to use.

While kind of 'pricey' the thought of losing an item that's costly itself & a necessary form of transportation these days was a huge factor in selection of this security device.As the collapse of society seems more evident every day, the thought of some miscreant 'Coming-Up'... was another motivating factor in investing in a good locking device.This lock is a Beast. It is quite heavy, so those concerned about weight may want to reevaluate choices. In this case, weight wasn't so much an issue. Theft deturent WAS.Cable bike locks can easily be cut with simple cheap cable-cutters quickly. This lock? Not so much.Can it be cut? Yup. Quickly & quietly? Nope.Can it be picked? Yup. Quickly? Nope.Good thick high-test chain was only option. Not liking paint or frame damaged by intense rubbing and/or chain banging, a high-quality sheath was highly motivational in this selection.While the weight can be a drawback, another small issue is the lock cylinder can be a bit finicky at times. However this can be sort reassuring in of itself, by being rather difficult for a novice 'picker' lacking proper tools.Appearance was another deciding factor as it looks tough, rugged & matches bike styling. And... in a 'pinch'...it could make a hellva defensive weapon.'Peace-of-Mind'... Who can put a price on that?When a beloved 'high-value' item has to be left unattended, it's nice to see that it's..."Right where I left it".

Durable

Needed a solid bike lock for my e-bike. The Kryptonite Keeper 712 is built solid. No lock is foolproof, but I think it would take a bit of work to cut through this one. I like the length of this lock, giving me plenty of slack. They would probably have to use and angle grinder to get through it. The chain and lock have some weight to them adding to the solid feel of the product. So far happy with this purchase.

very nice lock thicker chains than it seems and the key works easy and fine. maybe not the best for colder climates or seasons as the lock can freeze up. need some wd40 or a lighter to heat up your key to fix that. as for colder climates I mean like 10F or less.

If you buy this, no1 is stealing anything you've got it connected to! It would definitely take some TOP of the line power tools for thieves

I love it. The quality and the weight of it is absolutely perfect!! My ebike will arrive tomorrow and I am going to carry my lock with me in a bag on the back of the bike. It's not too heavy but excellent made. Thank you!

The lock and chain is bad ass. Some people wanna say it's weak or the key is jammy but that happens when it's not properly inserted. I noticed that and now I make sure you ndo that and I have no issues. It is so fat and thick yet the weight was not even bad. It wraps around my frame easy . It really looks nice with the sleeve that covers the chain. It would take along to cut this and they would need some tools that would look to obvious 😂. This and a cable bike chain would make it more of a challenge. If you on a budget then this chain is price and quality. The delivery might be a day but it's worth the wait.