The ONGROK 2 Piece Grinder uses a neodymium magnet which keeps the lid securely in place, so it's easy to open and access your herbs. This metal herb crusher is crafted out of solid, aircraft grade aluminum. Inside of the aesthetic finish, this grinder uses 33 triangular shaped teeth, to provide a medium-to-fine grind, every time. This is a reliable spice and herb grinder that you can count on. This herb and spice grinder has a diameter of 63mm, making a good size to be portable, and large enough to fit a small/mini humidity pack in the bottom chamber for long term storage.