AX-Edge Keytar: Modern Convenience To complement its striking good looks and killer sound set, the AX-Edge has many convenient features that greatly expand its usability for today’s keytarist. The USB memory function provides full backup capability, so you’re always ready if disaster strikes. It’s also a capable master controller for rack modules or plug-in synths. And Bluetooth MIDI and nearly four hours of battery life free you from wires, so you can throw caution to the wind and leave it all