Headset Buddy Female RJ9/RJ22 to Male 2.5mm Headset Adapter (RJ9-PH25) Female RJ9/RJ10/RJ22 to Male 2.5mm plug headset adapter Convert your RJ9 Phone Headset to 2.5mm Save money by using your existing headset! Does not work with RJ11 (which is the size of the phone jack in the wall, larger than headset phone jacks) 1 year warranty, 100% Satisfaction Guaranteed!