Grind to perfection with a Tsunami Sunken Top grinder. This 4-piece grinder is 63mm, which is a mid-size device that can fit most user’s needs while still being portable. Take it on the go in a purse or backpack. The lid has a sunken shape that looks like a bowl on the top. This minimizes the space in the top grinding layer, making the ground product drop through to the next chamber faster.