638-CD Combination Drainable and Adjustable Louver638 CD Combination Drainable and Adjustable Louver MADE TO ORDER Lead Time 2 3 weeks Custom Sizes Available Click here for Submittal The 638 CD combination drainable and adjustable louver is designed to prevent water penetration in building exterior walls for non wind driven rain applications. Water is channeled away from the face of the louver via built in drain gutters into vertical downspouts that allow the water to drain at the sloped sill. The