How does it work? It's a ball, attached to a chain. Oh, attached to a time lock. How cool is that?
The Study Ball is a prison-style, steel ball-and-chain that stays on as long as you need to keep you focused on your task. Weighing in at 21 lbs, it's possible to lug around, but why bother. Unless your office begins to fill with smoke, you're not likely to lug this thing around voluntarily.