Volume Sync allows you to control the volume of any of your devices from one device. Instead of changing them all manually or messing with apps to automate the volume when you are in certain places, you can instead set the volume once on one device.Volume Sync has a 7 day free trial. To use it longer purchase a key for $.99 here: https://play.google.com/store/apps/details?id=com.VolumeSync.keyPermissions Required:All Permissions required are needed in order for GCM to operate. GCM is Google Cloud Messaging which allows for the volume to be pushed to all your devices.Great for turning down your devices in class after listening to music. You can turn down your tablet in your bag with just your phone!