PRODUCT DESCRIPTION The rectangular valve box is designed to protect manual and automatic irrigation control valves, as well as meters, filters, and quick coupler valves. It is constructed from high-density polyethylene (HDPE) which enables it to stand up to UV, freezing and lawn equipment. Mousehole-shaped openings in the bottom of the box allow up to 2-inch pipe to pass through without cutting. The reinforced lid snaps securely onto the box. We recommend using the optional valve box base with the standard valve box, installing the valve box lid at grade level, and applying gravel beneath the base to promote drainage and prevent settling. Compatible with Orbit’s preassembled manifold system and components, as well as valves, filters, pipes, and fittings from Orbit, Hydro-Rain, and other major brands. For outdoor irrigation use with cold water only. FROM THE MANUFACTURER Extension valve boxes can be used in locations where the standard-height valve box isn't tall enough. It is made of the same durable, long-lasting materials as the standard valve boxes to keep your valves free from sand and dirt and the impact of weather. Extension valve boxes are available in 12 In. and 20 In. sizes.