Fittings between the pipe and head that are used to absorb surface impact of the head and prevent breakage.

a threaded connection between pipe and sprinkler allowing movement to be taken up in the threads rather than as a sheer force on the pipes. Also used to raise or lower sprinklers to final grade.

A flexible joint or pipe connecting a sprinkler head to a pipe. The swing joint is intended to provide protection from damage. In larger applications (institutional or golf course) it could be a series of three 90-degree street ells with schedule 40 pipe nipples in between the ells.