Aluminium pollen grinders are an advanced version of herb and spice grinding equipments and very popular . Basically its a 4 piece grinder with third and forth compartments .The pollen grinder ,4 part grinder or catching herb grinder is made up of 1) a top section with teeth on the underside 2) a section of lower teeth 3) screen and a 4) compartnment to catch the finer particles that fall through the screen . Herbs are placed in between the teeth, then the top and bottom are placed together and twisted . The twisting motion moves the teeth together and the herb gets caught and broken down into smaller particles. The size of the particles is determined by how much time was spent grinding. The longer the herb has been ground, the smaller the particles will be.Comes in various sizes from 1.25 inch to about 8 inches . Please view our collection of both 4 part grinders and 2 part grinders below .