KryptoniteNew York Chain 1210 Security Disc Lock (100cm), Black/Orange

I bought this to use with my bicycle when I take it to university. Overkill? Perhaps, but I'd rather be safe than sorry.After several months of hauling it in my backpack (along with laptop, books, toolkits, and more!), I decided to start leaving it locked up at university to save me some back trouble later in life. This is a rather heavy lock (I would weigh it if it was at home with me), and actually weighs more than my bike itself!As for security, it's great. No one is getting through this without extreme difficulty. I only say that because any lock can be broken given enough time and patience; I'd be more worried about a potential thief destroying/stealing what the bike is actually locked to, it'd probably be easier.If you're going to be using this lock with a bicycle that has quick release wheels like mine, I'd advise you purchase the lock alongside a cable, such as the  Kryptonite Kryptoflex 7 ft Cable Lock (10 mm x 213 cm) , which you can snake through your wheels and lock up to this chain.You get 3 keys with this lock: one main key that has a blue LED inside (useful for seeing the lock in the dark, but I've not had to use it yet, personally) and 2 spares. If you do buy, remember to register your keys with Kryptonite should they get lost or stolen (they have numbers on them).All in all, very happy with the lock. I'd gladly leave my bike all day at uni without fear of it going walkies... well, ridies.

Right now I use the chain for when I go on trips into London for added security and it has not let me down.Pros: heavy duty and well made, sold secure goldCons: it is very heavyYes the chain is heavy, but it is a chain so you get what you pay for, I personally wear it around my waist or coiled on the top tube of my bike.The lock that comes with it is nice and solid and I use it at uni outside of London with just a small kryptonite cable which does the trick, but for when I am in London both of them are on my bike and I have good piece of mind that i will be there when I return.

I am only going to give a four star rating because the Amazon delivery person left my parcel on the doorstep for nearly 90mins despite the electronic receipt saying I had received it in person - Amazon you need some improvements.Back to the product itself.... Wow, this is one heavyweight chain and lock that will protect your pride and joy bicycle. Comes with three keys, one of which has a little light on the fob for night time use. Kryptonite seemed to have thought of everything. Okay this isn't exactly cheap at nearly £80.00 but if you are looking to keep secure a mountain bike or road bike, this is worth considering.

Bought this for my son who had his bike stolen. It was secured by a bike cable lock which was an expensive one, they just snapped it in a few seconds. This chain and lock are quite heavy but I'm confident they won't be snapping this unless they come back with an angle grinder. Expensive but but well worth the money.

Good substantial lock...Quality throughout.So why Four? Because it's BITCH heavy. Forget lumping this mother anywhere, unless you're a maxed out Tough Mudder/RMC/ Triathlete kinda dude who needs extra baggage aboard to facilitate further and fuller upper body development!Much more a weapon to nail down gear in your garage...or unless of course, 'they' don't mind you leaving it permanently shackled to the shed/railings where you intend to leave your horse.God knows what the full-on yella peril must weigh....but...no-one's gonna nick your Mare with an artic' truck swinging off it...to be fair!

This is a serious chain, gives you confidence just looking at it. I use it in conjunction with a  Kryptonite Kryptoflex 7 ft Cable Lock (10 mm x 213 cm)  around the wheels and saddle.When using this for the first time I was able to leave my Smart E-bike (minus the battery and control panel) without unduly worrying about it being there when I got back. BTW The insurance does not cover the loss of the battery so if you have an e-bike you will swap the weight (3.6kg) of the chain for the battery when you leave, I think my battery weighs about the same as the chain (it is heavy).Overkill for anything under £500.

Chain is very very good (be careful about the weight) if you carry it in a back pack the weight is significant. I read some reviews about the lock that could be difficult to open and so I bought a WD-40 but still did not need it to use it

Feels really secure.Use it to lock up my Suzuki Bandit every day at work. Several bikes have been tampered with but no one has touched mine as this lock looks impossible to break into. Could be classed as a visual deterrent...It also drove my insurance costs down by more than the cost of the lock for 1 year.I will probably end up buying another to leave at work as it’s really heavy...