White push on 1 inch pipe clamp to attach Greenhouse Film to Hoops and purlins. These hoop house clamps are made of ABS so they don't have the Chloride that deteriorates the UV protection of 4 year Plastic. They work with any hoop or purlin material that measures 1.25" - 1.375" in diameter.  If your hoops are made of PVC, keep the 4 year plastic from touching the PVC with a thin layer of tape and clamp over the outside with these clamps.  Spacing recommendations of 2-4' depending on the windiness of your location.