The PS-640 is part of Power Sonic PS range of sealed lead acid batteries (often referred to as VRLA) which have been specifically designed for general purpose and standby applications. The 6V 4.50Ah offers excellent performance in a wide range of applications including security and fire systems, medical devices, emergency lightings and UPS systems. FEATURES • Absorbent Glass Mat (AGM) technology for superior performance • Valve regulated, maintenance free spill proof construction • Power/volume ratio yielding excellent energy density • Rugged vibration and impact resistant ABS case and cover • Gas recombination technology • 5 year design life • Approved for transport by air. D.O.T., I.A.T.A., F.A.A. and C.A.B. certified Model Number PS-640 Dimension Normal Voltage 6V Length: 2.76”/70mm Capacity @20HR (AH) 4.50Ah Width: 1.86”/47mm Capacity @10HR (AH) 4.10Ah Height: 3.94”/100mm Weight: 0.8kg/1.8Ibs Recommended Charger: PSC-6500A-C PSC-6500-PC PSC-6100-PC PSC-61300-PC