【Best Winter Freeze Protection Backflow Cover】5-layer optimal insulation design，forming a closed-loop protection system of "defense - insulation - barrier".It provides optimal freeze protection for backflow valve systems and sprinkler valve systems in harsh winter conditions. 【Size Description】The sprinkler valve cover outer size is 16"W x 20"H. Due to the 5-layer thickened material, the inner dimension is slightly smaller. Before purchase, measure the outermost width and height of your back flow preventer,sprinkler system ,irrigation system,pipe insulation,Well Head . Ensure: Backflow Width + 3" ≤ 22" W, Backflow Height + 3" ≤ 34"H. 【Superior Insulation Materials】The backflow insulated cover's insulation layer is Lofty bonded fiber, featuring a 3D network structure for better insulation, durability, and long-lasting thermal retention vs. others. Its aluminum foil layer is made of 99.3%-99.9% pure electrolytic aluminum or aluminum alloy sheets, an industry-leading "barrier material" that maximizes external cold air blockage. 【Reusable & Cost-Saving】This outdoor water pipe insulation cover is constructed with top-tier industrial-grade materials. The outer layer is heavy-duty 600D coated waterproof Oxford cloth, capable of withstanding heavy rain, blizzards and other severe weather conditions. Reusable multiple times, it helps you save significant costs annually on sprinkler valve system replacements and winter pipe system repairs. 【Customer Service】Please feel free to contact us if you are not satisfied with this pipe covers for outside, and we will offer you a satisfactory solution within 24 hours! SUNICO Backflow Preventer Insulation Cover (5°F) - 5-Layer Optimal Insulated Design Sprinkler Cover for Outside,22" W X 34"H, Backflow Insulation Cover for Sprinkler Valve ,Winter Freeze Protection