Hydro Flow?/Netafim?s 6 in staple is used to secure irrigation lines to soil surfaces. The U shaped staple design is recommended because it is less likely to pinch the tubing. Use one staple every 3 feet in sandy soils, every 4 feet in loam and every 5 feet in clay. Use 2 staples over tee, elbow and cross fittings. Can be used above or below ground.