"Caution - Buried Pipe Line" Sign By SmartSign | 7" x 10" Aluminum Heavy-duty, 40 mil thick, rust-proof aluminum Made of 96% recycled materials Durable, plastic laminate protects against weather, abrasions, and chemicals 4 mounting holes for screws or nails Rounded corners for longer life and simple installation For indoor or outdoor use Outdoor durability of 5 years