The 1” Blow-Out Flush Kit is an essential maintenance accessory for protecting 1” double check valve assemblies (model 350 and 350XL) during the winter months. This kit enables safe and efficient removal of water from the backflow preventer and connected irrigation lines, helping to prevent freeze-related damage. Easy to install without special tools, it’s a must-have for irrigation systems and other seasonal plumbing applications requiring proper winterization.