Pentair® Stark B4873A&B Fiberglass Nut & Bolt - This nut and bolt are constructed of fiberglass. Nuts are threaded metal fasteners that are used to connect two materials together. When paired with a mating bolt the nut is able to fasten parts together securely. Bolts are fully threaded, which provides an extremely strong and reliable grip connection. Made for easy installation and use, these parts will help ensure the best service life possible.