Extra long stand-by time
Compatible with original chargers
Specific intelligent Li-ion PCM, rechargeable Li-ion battery
Replacement battery for your phone provide you an alternative

High capacity and low impedance, no need to worry your mobile phone running out power on the go
Integrated power management circuits - protect against over-voltage and under-voltage conditions and maximize battery life between charges, minimize charge time, and lengthen overall battery life, provide the best possible performance
Easy to replace the battery and awaken your phone, keep you at the most recreational state
High quality replacement battery
Compatible with: 
Sony Ericsson V800 W900 Z800 K510 K790 K800 M608C P990 W300  W830 W850 W958 Z610 W880
And more compatible types were not list entirely
Rating: DC 3.7v 650mAh

1 x BST-33 Battery for Sony Ericsson K800 W300