The Butt Weld (B4, B8) check valve is a one-piece body machined from bar stock, eliminating porosity concerns and providing uniform density for more consistent welds. Made to ASME/ANSI B16.25 for schedule 40 pipe (B4), or schedule 80 pipe (B8) it carries rugged, dependable Check-All trim with a wide variety of seat materials and cracking pressures to choose from.