A copper supply line or return line used mainly in radiant staple-up systems. Basically an elongated site-built manifold, headers are useful because they allow the installer to tap off of a single, long copper line to feed multiple circuits of tubing within a single zone. Headers bring the heated fluid to the circuits instead of forcing each circuit to return to a small, centralized manifold. This method prevents congestion and snarl and gives the installer more flexibility in the placement of feed and return lines.