The ABUS Granit PLUS 640 is one of two ABUS locks that I use on a regular basis. As a D-shaped U-lock, it is a classic option for reliable and proven protection. It is light enough and small enough to carry in a bag, but stout enough to protect your bike from theft. The shackle, which is double bolted into the lock body and made of 12mm hardened steel, is also coated in rubber so that it will not damage the finish on your bicycle. The lock itself weighs less than 900 grams, which is quite light considering the amount of protection it provides.