The 21" x 16" Insulated Backflow Bag Green is a heavy-duty insulated bag designed to protect irrigation backflow preventers from freezing, moisture, UV exposure, and general outdoor wear. Its thick insulation and durable, waterproof outer shell ensure that backflow assemblies remain operational even in harsh weather conditions. Double-stitched seams, a Velcro bottom closure, and rust-proof brass grommets provide extra strength and secure installation, while the bag’s flexible design allows it to fit snugly over standard 21" x 16" assemblies. This bag extends the life of backflow preventers and keeps water systems safe and functional year-round.