Rain Bird VB Standard Valve Box Lid Rectangle Overlapping Black Polyethylene Lid Only. Work faster and easier with a Rain Bird Valve Box. We've created unique knock-outs for easy pipe placement and reduced installation time - so no more tedious cutting. And the knock-outs slide back into place above the pipe to keep out dirt on backfill. All Rain Bird Valve Boxes were engineered to maintain their horizontal and vertical integrity under load, even with the knock-outs removed. Other unique features include a bolt hole knock-out to help keep critters out of the box when the locking bolt isn't used and a shovel access slot on the side of the box that makes it easy to remove the lid.