Brennan 1404-04-04 Steel Pipe Fitting, Straight, 1/4-18 NPTF Male x 1/4-18 NPSM Female Swivel Adapter fitting for connecting pipes with different thread Male National Pipe Taper Fine (NPTF) threads on one end, female National Pipe Straight Mechanical (NPSM) thread on the other for connecting two types of pipe Hexagonal nut for use with a wrench Swivel female end for flexibility Steel for durability