Our Pro Series valve boxes were designed for the professional contractor and heavy-duty use, and offer superior strength for non-residential and utility applications. All Pro Series Valve Boxes and lids are manufactured in Lindsay, California, and contain UV inhibitors to prevent discoloration and cracking. Competitive Benefits: Thicker wall dimensions for increased strength and durability, Reinforced covers for heavier loads, Reinforced ribs offer exceptional sidewall strength, Stainless steel nut on boxes for bolt-down capability, Overlapping covers prevent dirt and grass from settling between body and cover Our Pro Series valve boxes were designed for the professional contractor and heavy-duty use, and offer superior strength for non-residential and utility applications.