Get the latest apps with the powerful Windows Phone 8.1 OS. Billy 4.7 features ASAHI DRAGONTRAIL GLASS, a damage resistant, more durable, & exceptionally responsive display. IPS HD Screen (1280 x 720). The thinnest Windows Phone in the World with its 7.2mm Ultra Slim Body. Fast processing with Qualcomm Snapdragon 200 processor with quad CPUs at speeds of up to 1.2 G Hz.