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.