The #13½ BT Winter Plug BlowThru Valve is an essential tool designed for winterizing pool and spa systems, helping protect plumbing from freezing temperatures. Constructed from durable nylon, this plug is built to withstand wear and tear during cold weather. The BlowThru Valve feature allows for easy air evacuation, making it perfect for clearing water from pipes and preventing freeze damage. With a nut included, it ensures a secure and leak-proof fit when installed, offering peace of mind throughout the winter season.