Internal Hex No.5 drive, countersunk head, coarse thread, type 17 point. Zinc yellow plated, class 3 coating or grade 304 stainless steel.
This screw is very well known for its strength and is specified in a lot of applications for this reason. Some of the most common uses are roof trusses, retaining walls, decking etc. The hex drive enables you to get an excellent drive grip and the type 17 point is excellent for drilling into hard timber.