Master Gripper #14 Self-Drilling Screw. The Master Gripper is a 1/4-14 x 2" snow guard screw with a type A milled point. These precision carbon steel self tapping fasteners are designed for metal roofs on wood purlins or decking. Features a 5/16" AF Hex Washer Head. The Master Gripper comes with a corrosive resistant coating to with stand all the elements. Comes with a tight sealing weather proof washer. When screwing down snow guards the use of Novaflex MR-150 is required.