Ketone Ethylene Ester, or KEE, is a strong, flexible, chemical-resistant material that can serve as a high-performing capsheet in a multiply roofing system, or as a membrabne for 2-ply flashing systems. Garland's KEE-Stone family of thermoplastic membranes utilizes a higher loading of Elvaloy® throughout the entire sheet via our proprietary "Open Window" technology, which ensures a better polymer blend for greater strength, flexibility, and durability.