Description 40yr ZXL Roofing Screws.  250pcs per bag. 40yr protection against red rust on the head & washer. Molded head cupped to completely hide EPDM rubber washer when installed. Small metal drill tip (no predrilling required!) Color match Woodgrip threads Larger 5/16″ head *Click here for more info and specs from the manufactures website *Recommended amount for screws is:   ~ 1 screw per sq.ft of roofing,   ~ 30 screws per ridge cap. (Usually 2″ screws for cap) Includes enough for normal amounts of rake, drip, & other accessories.  Add more for valleys and hips.  (Amount based on rows of screws every 2′, with 4 screws per row, per panel)   Not sure what materials you need for your roof? Give us a call!  We can help with that, and any other questions you have!