The Sony Ericsson BST-33 is a high quality non-genuine replacement lithium-ion rechargeable mobile phone battery. This replacement battery is manufactured to CE & UL standards, is ROHS compliant & can be used as a cost effective alternative to genuine branded batteries. Specifications: 3.6v 800m Ah Compatible with the following mobile phone models: Sony Ericsson K200i, K530i, K550i, K790i, K800i, K810i, M600i, P990i, V800, W300i, W610i, W850i, W880i, W900i, W950i, Z530i, Z610i, Z800i, Please note: New batteries will achieve optimum performance after two or three complete charge & discharge cycles. * Figures are approximate & are dependent on SIM card, phone model & settings, network & usage.