Our weighted tubing remains on the bottom when filled with air. The blue color makes it easy to hide in your pond. It is designed for lake and pond aeration, making installations fast, clean and neat! Also removing airstones for replacement and cleaning is also made easier with no weights or bricks to move. The 5/8 ” I.D. (WD1) tubing has an O.D. of 1.125”. Use the smaller 3/8” I.D. (WD2, has an O.D. of 5/8 ”) weighted tubing for smaller volumes of air, shorter distance or with higher pressure compressors. Call for large quantity discounts. WD2 made in Canada, WD1 made in USA.