At 57mm, this portable grinder fits comfortably in both the hand or pocket, so you can take it everywhere you go. Using modern Computer Numerical Control this grinder was fashioned to produce flawless threading and fittings that screw on perfectly. Manufactured from premium aluminum, the 4pc Space Case Grinder Medium 57mm will survive wear and tear, lasting longer than the average grinder. The diamond cut shredding teeth will glide through the stickiest of dry herb with ease. When the dry herbs are evenly grinded it will fall through the hole of the lid to the second chamber. As the herbal blend falls into the second chamber, pollen falls through the stainless-steel screen allowing the user to save it for later. If you are looking for a durable, quality built grinder the 4pc Space Case Grinder Medium 57mm is the perfect grinder for you.