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

Beautiful quality. Will stop all but professional well tooled thieves. It’s more than good enough. Great product.

Works well for an electric bike. It's fairly heavy so I would not want to carry it around on a road bike. However, it feels solid and I don't really notice the weight when I have it in my ebike's panniers. I recommend getting a Velcro strap to wrap around the chain so it doesn't flop around in your bag. The fabric sleeve around the chain is soft and I haven't felt any concerns about it scratching my frame.

Seems good, only moderately heavy, apparently secure in locations which aren't obscure, not too expensive.

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.

Security:this lock looks and feels safe for any type of bike or e bike

Great fit and keeps my bike safe

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".

This thing is a BEAST. Really high quality, I can't imagine anyone getting through this thing. It was actually more than I bargained for; but that was my fault for not reading the specs where it says it weighs 7 pounds. I returned it and got a smaller size, but that's all my fault and no reflection on the quality of the chain. Great if you're looking for a high quality, super-heavy-duty chain!