HEMPER Aluminum Grinder 4 Piece LargeDescription These 4 piece Hemper branded grinders are lightweight, durable, and efficient! While 2 and 3 piece grinders get the job done, 4 piece grinders allow you to make the most of all of your flowers and waste nothing. While they feature relatively the same design: two pieces on top to grind, followed by a screen and kief catch. Kief or pollen is essentially the super potent piece of your herb called "trichomes". The kief then collects in the