The Spintso Microcom Push To Talk (PTT) Headset is compatible with all Spintso Communication System. Designed to be used by the fourth official, this headset only transmits when the fourth official presses the "talk" button. This allows the fourth official to conduct his or her duties with substitutes and bench personnel while not disrupting the communication between the three other referees. Listen in to the communication at all times, and transmit only when needed. This is a must have for referees using communication systems with fourth officials