Flarm Speaker is an audio warning device for Flarm traffic messages. When alert message from Flarm is decoded, device will make audible sound. Generated sound depends on message severity (Alarm type).Flarm Speaker also features phono output with 3.5mm mono jack located in the top center at the back. Speaker can be turned off only when phono jack is plugged in and slide switch is at AUTO position. There are three volume adjustments available with push button on the back of the device.