Includes four 6" rubber membrane air diffusers to handle .8 - 3.4 CFM air flow. Our air diffuser manifold allow you to hook up several air diffusers to a single air line. Manifolds include a check valve to prevent water from filling your air line when not in use. A polyethylene underlay keeps diffusers from settling into the mud and prevents sediment erosion during operation. Standard air diffusers are 6" long. Standard airline connection is 1/2" poly tubing.