An elementary conduit is a conduit with no recognizable active signal stage besides its input and output. An early example still very commonly used is David Buckingham's BFx59H, which transforms a B-heptomino into an inverted Herschel in 59 ticks. The BFx59H elementary conduit is a component in many of the original universal toolkit of Herschel conduits. (An extension of the same naming convention is used for elementary conduits, with the first and last letters of the name specifying the input and output signal objects. As with Herschels, an arbitrary orientation and center point is chosen for each object. "Fx" means the signal moves forward and produces a mirror-image output; see Herschel conduit for further details.)
Theoretically an elementary conduit may become a composite conduit, if another conduit can be found that shares the beginning or end of the conduit in question. In practice this happens only rarely, because many of the most likely branch points have already been identified: glider (G), LWSS (L) or MWSS (M) or HWSS (HWSS), Herschel (H), B-heptomino (B), R-pentomino (R), pi-heptomino (P), queen bee shuttle (Q), century or bookend (C), dove (D), and wing (W). A Herschel descendant (H') might qualify, due to the elementary conduit that can be seen in the p184 gun. However, there are very few simple conduits that produce Herschel descendants without Herschels, so in practice this is not a useful branch point.