The Rheem AP11111 Insulation Cavity is designed to improve the energy efficiency of Rheem water heating systems. This insulation is made from high-quality materials that provide excellent thermal resistance, helping to minimize heat loss. It is specifically designed to fit various Rheem models, ensuring a perfect fit and easy installation. The insulation cavity contributes to maintaining optimal temperatures within the system, enhancing overall performance and reducing energy costs. Ideal for both residential and commercial applications, this insulation is essential for maximizing the efficiency of your Rheem water heater.