Schedule 80 Steel Pipe Nipple, 1-1/4-11-1/2 Male NPT, 4.00 Inch Long

Seamless pipe has no weld seam running along it, which means there's no joint that can weaken under pressure or stress. For high-pressure applications, that matters quite a bit. A welded nipple has a heat-affected zone along the seam where the metal behaves differently than the rest of the pipe. Seamless stock avoids that entirely, giving you consistent wall strength all the way around. Schedule 80 wall thickness adds to that by being noticeably heavier than standard Schedule 40, so you're getting both the material integrity and the added wall beef working together.

The key callout is the thread. This nipple is 1-1/4-11-1/2 male NPT on both ends, so it mates with 1-1/4 female NPT threads.