Kryptonite New York Fahgettaboudit Chain w Disc Lock - 3 Ft. 3 In./--

The lock has the highest rating from Kryptonite.

Pros:
very secure
nylon cover to protect bike
long chain to put around almost anything

Cons:
locking takes longer than a u-lock
very heavy (not a serious negative point since this is expected for a lock this secure)

if u want the best security, this is the lock to get. if u really prefer a u-lock, they offer the same security rating in a u-lock as well.

I received the lock promptly and put it to use right away. I have been very pleased with the added security that this locks provides both with it's ability to withstand attacks and in it ability to simply intimidate a thief. It is ungodly heavy, but I can justify that considering my bike is worth it. Why by a 20 dollar cable to protect a $1300 bike?! It's in a investment that pays off every time you come back to find your bike still there waiting for you at the bike rack.

The chain is heavy, which is fine by me. That also means that it is strong and will probably deter all but the most determined criminal. The issues with this particular model is that the protective sleve will easily slide off of the chain if you aren't careful. Also, there is not enough room in the links to put the lock through in any but the ones on the end, making it very difficult to wrap tightly around an object.

Other than those two issues, the thing is a beast.

Before I purchased this lock, I carefully read what other Amazon purchasers had to say and the common theme was "it's heavy." Yes, it certainly is...I'd say just under 15 pounds to be exact (including the actual lock and chain). BUT, if the durable manganese steel wasn't formed into six-sided hexagonal chain links, bike thieves would be stealing sweet rides all the time. Although this is the only lock I purchased, I am extremely confident that someone can not cut this lock and steal my bicycle, even on the streets of NYC. So, if you want to have a long-lasting relationship with your bicycle, you'd better start working out those shoulder muscles because this lock is the best anti-theft device on the market...even if it is a pain to schlep around.

Excellent lock, this thing could stop a tank. It would've also been easily mountable due to the chain design. I had to return it though due to the weight. It weighs approximately 10 pounds and the extra weight won't work for long rides.