What type of ends do pipe nipples have?

Pipe nipples are short lengths of pipe that are usually used to connect two other fittings or pipes. The ends of pipe nipples are typically threaded to allow for easy connection to other pipes or fittings. This threaded design enables the nipples to be securely screwed into or out of other components, ensuring a tight and leak-resistant fit.

Welded ends are not characteristic of pipe nipples since they are designed for quick connections, whereas flanged ends involve a different method of attachment that uses bolts and flanges. Closed ends may refer to some specific types of fittings or plugs but do not accurately describe the standard design of a pipe nipple. The threaded ends make pipe nipples versatile and widely applicable in various plumbing and piping systems.