Schedule 40 Steel Pipe Nipple, 3/4-14 Male NPT, 4.50 Inch Long

A 4.50 inch close nipple with 3/4-14 Male NPT threads on both ends fits right into standard 3/4 inch NPT fittings and valves, so yeah, extending a line by a few inches is exactly what this piece is built for. The Schedule 40 wall thickness holds up well in industrial conditions, and the black steel construction is solid enough for regular shop use. Just keep in mind no thread sealant comes applied, so you'll want to add your own tape or compound before threading it in.

With 3/4-14 male NPT threads, it matches standard 3/4 inch NPT female threads. The 14 threads per inch is the normal pitch for 3/4 NPT, so it should screw into a 3/4 NPT female fitting.