Feature-packed passive noise reduction headset The Echelon 25XT packs additional comfort and performance features onto the solid Echelon platform. The 25XT includes Telex??s innovative cell phone/MP3 adapter that allows you to attach both your cell phone and MP3 player at the same time. No more switching cords! For inbound and outbound commucation, simply mute them both at a touch of a button.