Extended Standby Mode - Sony's new power save feature

With Extended Standby Mode, you can increase your Xperia™ smartphone's standby time with up to four times. Available for Xperia™ P, Xperia™ U, Xperia™ sola and Xperia™ go with the Ice Cream Sandwich upgrade. Turn it on in the power management menu. Read more on
http://developer.sonymobile.com/2012/10/05/learn-about-extended-standby-mode-sonys-new-power-save-feature-video