Upgrade distribution head (aka manifold) for air drills and other air-distribution systems. Improved internal flow over many OEM designs, resulting in more uniform product distribution among the outlets as well as less seed damage. The rubber cap in center can be replaced with a rubber cone (highly recommended; sold separately), or with a SeedVU. Heads w/ 2.5″ inlet. 1″ outlets for JD & Case-IH/Flexicoil. 1.25″ outlets for certain other OEMs.