This is a unique product. It's a two part plastic form that lets you trap a bearing between the two halves and force a spray through the bearing. No guessing, it goes right through. The hole in the top of this gizmo perfectly fits a straw from a spray can. You can either force a cleaner through this thing (and through the bearing) or you can soak your bearing normally, and force everything out of it with a can of compressed air. More convenient than carrying around a dremel tool. Easy to use and clever.