Castle makes a stable impression, mount unusable

The castle is really very hard to have the underestimated. But it makes a very strong impression. It is very easy to open and close, the key light is very convenient. Unfortunately, the holder is unusable on my bike. The tube is not round and the holder sliding around and keeps not close the frame. Then still hangs heavy lock on it, you loose even more. Have it equal removed again and not dare to ride it. Will now always take hold in the backpack, the castle - shame.