Sloan G2 RESS-C-1.28 Optima Plus Battery Powered, Automatic Retrofit for Toilet Flush Valve - 1.28 GPF PERMEX Synthetic Rubber Diaphragm with Dual Filtered Fixed Bypass Flex Tube Diaphragm designed for improved life and reduced maintenance ADA Compliant OPTIMA Plus Battery Powered Infrared Sensor for automatic "No Hands" operation Infrared Sensor with Multiple-focused, Lobular Sensing Fields for high and low target detection Latching Solenoid Operator Engineered Metal Cover with replaceable Lens Window Courtesy Flush Override Button Four (4) Size AA Batteries factory installed "Low Battery" Flash