NOTE: HEADSETS PLUGGED INTO CORDLESS PHONES MAY HAVE LOW MIC VOLUME.. Most cordless phones have a 2.5 mm headset jack which will accept our 2.5 mm cell phone headsets. For more durability, we can use a corded monaural office headset combined with a 2.5 mm quick disconnect cord. The Sennheiser 2.5 mm to QD connector cord - it’s 6” in length , catalog number 1782 The Leitner 2.5mm QD connector cord - it's 8' in length, catalog number 2356 The Executive Pro 2.5mm to QD connector cord - it's 6" in length, catalog number 1860 May work for wireless: MAY Executive Pro male 2.5mm to male RJ9 adapter - 18" in length, catalog number 1375 Make sure to set the expectations correctly