A Grinder That Works Hard So You Don’t Have To. Look, no one’s out here asking for a grinder that sparkles like a unicorn or plays a jazz solo when you twist it. You just want a reliable, no-BS, solid piece of gear that actually grinds and doesn’t break the bank. Boom. This is it. The 50mm Zinc 4-Piece Grinder is compact, durable, and surprisingly satisfying to hold.