ERGO offers you nothing but premium quality grinders so that you can get an effortless grind to enjoy with your favorite legal smoking herbs. Made of aircraft grade aluminum, these grinders feature an ergonomically designed lid that is easy to hold and twist so that you can grind easier. The lids are perfectly fitted with strong magnets so that they stay sealed with ease and you dont lose anything due to spillage. Each grinder is designed with diamond-shaped teeth that are sharp to give you the perfect consistency to your herbs, and this 4-piece grinder features a removable screen so that you can easily take it out to clean or replace. These grinders are high-quality with a lifetime manufacturers warranty, so you can continuously get the perfect, effortless grind no matter what!