Building upon Sony Ericsson’s hugely popular Z520a, the new Z525a adds Push-to-Talk 
functionality to an already feature-laden phone. The compact and stylish clamshell handset also includes Bluetooth connectivity, a VGA camera, messaging, special lighting effects for incoming calls, and seemingly endless opportunities to customize the look of the phone. The Push-to-Talk (PTT) feature offers a fun and easy way to stay in touch with friends, colleagues, or family with just the touch of a button.
This addition also inadvertently fixes one of the biggest complaints of the Z520a - the button to activate PTT replaces the dedicated camera button on the outside of the phone. The camera button was prone to being accidentally pressed while talking on the phone or while in a pocket. The PTT features a lock which minimizes the problem although it still could have been better located elsewhere.
The phone features Style-Up exchangeable front and back covers that allow users to change the exterior to match their mood or wardrobe. The customizable options go beyond wallpaper and ringtones as it provides several themes to choose from that radically change the look of the menus. The phone also allows the user to set a photo, ringtone, and lighting effect that can be unique to each caller. Sony Ericsson Z525a Review - Mobiledia