I saw a review of this puzzle by chance and it sounded intriguing, and as a metal fabricator the brass sphere just sounded kinda neat.
Impossible describes more than one aspect of this. If you are a sorcerer maybe you’ll crack it “quickly” but otherwise it’s good for at least 10-12 hours of frustration and cursing. But in a good way.
The machining and construction are both excellent and it’s highly unlikely you will solve it by accident, and impossible with some kind of trick or cheat. The brass will slowly develop a nice patina as you play with it. Definitely a good pick if you rank value in time to solve and construction.