A Zinc Coated Steel hex washer head tapping screw with spaced threads and a drill point which drills its own hole. Beneath the head is a conically shaped circular steel washer, bonded to a similarly shaped rubber-like (neoprene) piece which has a slightly smaller outside and inside diamter. When these washers are assembled (rubber side down) to self-drilling screws, those fasteners become "sealing screws". When properly assembled, this washer: (a) offers protection against leakage; (b) provides load bearing qualities superior to that of a regular flat washer; (c) reduces the chance of the fastening becoming loose due to vibration; (d) minimizes damage to the mating surface caused by contact with a steel washer. Sealing screws may be used to attach roofing or metal walls to steel frames. Consult a self-drilling screw selection chart for the correct size. Self-drilling screws offer economical benefits: reduces labor and tooling costs; reduces or eliminates drill bits and taps. Type BSD Thread Pitch: May be used to attach plywood, soft woods or composition board to metal, or attach metal to metal. Tek screws, also known as self-drilling screws or self-tapping fasteners, are fairly common pieces of hardware. Aside from the drill tip of the screw, Tek screws look like standard screws. The tip of a Tek screw, known as the drill tip, includes a small carving piece at the end of the screw. This piece is used to establish a small hole in applications by first tapping the screw against the application before driving it in. This provides a better starting point for drilling the screw. It also saves time by eliminating the need to drill a hole before installing a screw or waiting for thread to catch. Tek screws are commonly used in the electrical industry. Typically, these screws are used in metal-to-metal and metal-to-wood applications. The most common are used in thin metal applications such as working with steel studs.