Castle is safe but ...

This is a the Ghetto-class castle that gets safely on any readily. Weighs over 2 Kg and comes mostly in the saddlebag. Sufficiently long to the Radl to connect securely. Key and mechanics super.
Exactly as it should be. 5 Stars

BUT: The front part of which is in the lock is solid metal, without gumming or protection, so that the heavy part of any bike frame incredibly fast beats rough paint damage.

Here you have to be extremely careful, so 3 stars. There is another way with a thin, robust plastic coating, then it would be 5 star, no questions asked.