Profile: Fiberglass Utility Supplies, Inc. produces valve products. Our brands include DOS-IR™. We serve agricultural farming, golf courses, horticultural farming, wetlands, conservation areas and drainage industries. We use high density polyethylene in sheet form, 3/8″ and 1/2″ thick to make the valve center, the guides and the doors. Our bolts, nuts and H-shaped operating clips on the valve doors are all made of 18-8 or 304 grade stainless steel. Our products are assembled of fiberglass, polyethylene, stainless steel and aluminum part. Our Dos-IR® turn-out gate is used in canal irrigation turn-out control, culvert pipe entrance and shut-off valve.