Stainless Phillips Pan Cheese Metric Machine Screws are used in conjunction with washers and hex nuts in order to fasten metal parts together securely. To ensure proper fit and quality of life, make sure to use machine screws with nuts of similar thread size and finish. Variants included in this assortment come in M3-0.50 & M4-0.70 coarse thread sizes and range from 6mm to 35mm in length. Full assortment contains sixteen (16) refills comprised of Hillman item numbers #3985 - #3991 and #45291 - #45299.