Pipe end has an insert in it
A fitting that forms an angle of less than 180 degrees (3.142 radians) from the straight flow. One connecting end has standard pipe threads, or is unthreaded and designed to accommodate a pipe. The other end has machine threads (straight threads other than pipe or hose series) designed to accommodate a tube, or is unthreaded and designed to accommodate a tube. It may have side or heel inlet(s). See also elbow, pipe; elbow, tube; and connector, multiple, fluid pressure line.
Classification: Threaded elbows and bends of iron or steel (other than cast iron or stainless steel) for pipes and tubes
NSN 5935-01-391-5692
NSN 5990-01-617-5156
NSN 5998-00-232-2137
NSN 5835-00-253-3453
NSN 6145-00-635-9957
NSN 5998-01-610-1141
NSN 5998-00-661-0380
NSN 6240-01-597-1941
NSN 5895-00-464-2304
NSN 7035-01-280-1119
NSN 5910-00-203-5856
NSN 6105-01-246-0008