Rain Bird PVBSTDEXT Valve Box Extension with Lid, Plastic, Black Body, Over Lapping Green Lid, 17 Inch Top x 18-7/8 Inch Bottom L. Reputations are built on hard work, not shortcuts. Just like PVB Professional series valve boxes. Made-in-America tough, these boxes are loaded with the features you need to get the job done right, without cutting corners. Even standard installations deserve professional performance. From reinforced sidewalls and bottom flanges to skid-resistant lids, the PVB Professional series is manufactured to our own exacting standards, using quality materials and rigorously tested for durability.