Crochet Hooks Steel crochet hooks in sizes 00 to 16 Hook size is in American size numbers and hook millimeters. Manufacturers are not consistent in their use of hook size. So, whenever possible, use millimeter size when purchasing crochet hooks. See also Crochet Hook Storage Cases.  See the Crochet Hook Information Page for hook size info, info about the new Interchangeable Head Set and info for Mystery Stole and similar projects. New!! Interchangeable Head Crochet Set Order quantities are preset to "1" If you want to purchase 1, just click on "Add to Basket" If you want more than 1, change the Quantity and then click on "Add to Basket"