This is a Hawker/Cyclon/Enersys 0810-0104 battery widely used in emergency lights. The Hawker/Cyclon/Enersys 0810-0104 8 volt 2.5 Ah Pure Lead battery is a popular replacement battery in many emergency lighting units --- BatteryGuy Supplies Enersys Cyclon, the most reliable Pure Lead Acid Battery in the Industry. Enersys Cyclon has Been Around Since its Inseption in 1973 and has Been Through Several Different Name Changes Since Then. Enersys Cyclon Was Known as Gates Battery and Hawker Battery in the Not so Distant Past. Enersys Cyclon Pure Lead Batteries are Known for their Superior Deep Discharge, Maintaining their Performance in Extreme Conditions, Long Service Life, Rugged Construction as Well as their High Rate Charge and Discharge. The Enersys Cyclon Battery Offers the Greatest High-Rate Power Density for Your Energy Dollar. Chemistry: Pure Lead Acid Dimension: 6.69" L x 1.48" W x 2.97" H Configuration: 1 x 4 D Cells in a Horizontal Row Housing Type: Steel Cased Cells in Shrink Wrap Connector Type: 0.187" F1 Faston Tabs