The Handiest Tool You’ll Ever Own Micrin Tool's Keydriver on keychain split ring. Micrin Tool Keydriver blister-packed on card. Micrin® Tool Company’s Keydriver is a durable, die-stamped, key sized tool  that offers your customers the convenience of always having a screwdriver as close as their key rings. Made from fire hardened steel, Keydrivers are nickel-chrome ...