Air manifolds are generally small in diameter with multiple 3/8" connectors which feed air to the 3/8" connections on the back of water jets. They can sometimes be found glued directly into the underside of air controllers.
(2) 1" Spiggot x 1" Socket x (8) 3/8" SmoothBarb air manifold for hot tubs or baths.
1" Socket x 1" Spiggot x (6) 3/8" Barbs
Air manifold system which can be cut to make 2, 4 or 6. Supplied with x1 plug.