Kryptonite Krypto Series 2 U-Lock

The internal dimensions are 83 x 178 mm, which is quite compact. It is designed for quick stops and locking to standard bike racks or poles, but you may find it tight if you are trying to secure your frame and both wheels simultaneously.

At 2.45 lbs, it is substantial enough to feel secure but light enough that most riders won't notice it while it's mounted to the frame. The included FlexFrame bracket keeps the weight centered and out of the way while you ride.

The double deadbolt mechanism locks both sides of the shackle into the crossbar. This significantly increases resistance against leverage attacks, as a thief would need to cut through both sides of the shackle to pry the lock open.

It is weather-resistant, and the built-in dust cover is specifically designed to keep grit and moisture out of the cylinder. However, like any mechanical lock, it is good practice to occasionally lubricate the cylinder to ensure smooth operation over the long term.

This specific model includes two keys. While Kryptonite offers a key registration program for many of their locks, you should check the packaging or the brand's website upon purchase to see if your specific unit qualifies for key replacement services.