Button Head 8 gauge-18 threads per inch x 12mm long screw class 3 coating
Button Head screws are for fastening into metal where a larger profile head is required.
The Class 3 corrosion protection system meets the requirements of ISO 9223 Category 3 (Outdoor application for mild and moderate environments).
AS 3566.2 (Self drilling screws for the building & construction industries) specifies the corrosion protection systems required on screw fasteners Classes 1, 2, 3 & 4 where Class 1 is intended for indoor application and Class 4 for environments up to and including ISO 9223 Category 4 (Severe industrial and severe marine environments).