Replacement mic muff fits all Telex PNR and ANR headsets with flat electret mic.Compatible with:Stratus 50 DigitalStratus 30XTStratus 30Echelon 20Echelon 25XTEchelon 150Airman ANR 500Air 3100, 3500, 4100, & 4105Stratus Heli-XT ANRMost other standard...