Street 90* elbows feature female pipe thread on one end for threading onto externally threaded mating parts and male pipe thread on the other end for threading into internally threaded mating parts. They come with either the same size male/female pipe thread or alternating sizes depending on the application. They are made for use with air, natural gas, oil, and water and are made of schedule 40 black iron which has a 150LB rating and is made for non-corrosive environments.