Window Fabrication Screw: Countersunk - PH - Self Tapping Thread - Self Drilling Point - Zinc Plated Countersunk Head: Designed for countersinking into the substrate for a flush or recessed finish Self Tapping Thread: A common thread design mainly used in steel applications Self Drill Point: For drilling into metals without the need for pre-drilling. A comprehensive range of self drilling screws used for the construction of a PVCu window/doors. Multiple uses for fitting a variety of hardware to frames where there is a steel or aluminium reinforcement present. Product Code: Size: Box Qty: PN123Z 3.9 x 25 x1000 PN124Z 3.9 x 32 x1000 PN125Z 3.9 x 38 x1000 PN127Z 3.9 x 45 x500.