Lot of (350) indented hex washer head pole barn screws with bonded EPDM neoprene washer.
These galvanized fasteners are #10 thread and are 1" in length with a 1/4" hex and have a 5/8" diameter rubber/steel bonded and heat treated washer.
This screw has a hi-low style thread and sheet metal piercing point designed for attaching metal roofing and siding to treated lumber.