drain the water from the air-line, can be also used as a outlet. Port Sizes available 1/2" and 1/4" Female. With 4 holes for wall-mounting use. Optional a mini automatic float drain and a mini ball valve are available for the bottom port to drain water. A 0.60 inch thick rubber pad is also available for keeping the manifold more away from the wall for more space for the mini automatic float drain.