Schedule 40 Black Steel Survey Monument Pipe, 2" x 18" Create substantial, durable survey monuments and reference markers with this 18-inch Schedule 40 black steel pipe . The larger 2-inch diameter and heavy-duty steel construction make it well suited for permanent survey monuments, property marking and control point installations. Sold individually. Key Features 2" diameter x 18" long black steel survey monument pipe. Heavy-duty Schedule 40 steel provides excellent strength and durability. Larger diameter provides a substantial foundation for permanent survey monuments . Ideal for property markers, control points, survey monuments and construction layout .