certainly the most secure lock, but it rattles. On the other hand, it can be easily opened and closed unglaublcih (with key, clear) and the length is very practical, even in difficult situations. I use seven (!!) bicycles padlocks and this is the best yet. I have been in almost 20 years has never stolen a wheel with U-lock, even if this part are in dimly lit train stations in Berlin (with exactly this castle and a> 1k-Euro-wheel) or a year alone in the backyard right hinrotten (ups) ... This is true but said so more for the type of lock than for exactly this castle.
