The X12 is a self-drilling screw with a drill point and 5/16" hex washer head. The drill point allows the screw to penetrate the steel without the need for a pilot hole.

The X1214 screws have 14 TPI and a #3 drill point capable of drilling through steel up to 5mm thick. Suitable for connecting LGS sections together. The X1224 screws have 24 TPI and a #5 drill point capable of drilling through steel up to 12.5mm thick. Used for connecting LGS sections to hot rolled steel. 

Driver bit not included.