Phoenix Star 4 Part Herb Grinder 2.5'' PHX608 is constructed of premium maximum-strength aircraft grade aluminum with 4-layer to make it stable and practical. The diameter of Phoenix Star PHX608 dry herbs grinder is 2.5 inches, so handy and convenient to carry. Its first layer is the top cap, the second comes with grinding equipment. Just put dry herbs into it and close the lid. Because the third has stainless steel mesh screen, which is helpful to filter very fine pollen into the catcher. After rotating the dry herbs grinder for several times, you can get smaller bitty on the forth layer, which can be burnt more fully to provide you more wonderful hits.