The WixeyTalk App works in conjunction with the Wixey WR300BT Digital Angle Gauge with Bluetooth output. It turns your iPhone or iPad into a remote visual display and provides a talking output designed specifically for visually impaired individuals. When the App is launched it automatically connects with your WR300BT. If you do not have a WR300BT Digital Angle Gauge you can use WixeyTalk in simulation mode. It turns your iPhone or iPad into a fully functioning standalone digital angle gauge. You can purchase a WR300BT here: http://www.wixey.com/anglegauge/index.html