It is precision engineered aluminum throughout and is built so solidly it should last you a lifetime. But it is shredded effortlessly in the top section and the rotating lid has a magnetic attraction to the lower grinding section. This keeps it in place and stops it falling off. It is that kind of attention to detail that our customers demand in their Pro Grinder. Anything left in the top section is often fibrous waste. Your shredded bud falls into the section below landing on a wire mesh screen. Everything screws together with military precision.