SENNHEISER 506488 Male 2.5mm to Female 3.5mm 1/8" Audio Adapter plug (Adapt Audio/Mic to DECT phone) SENNHEISER Male 2.5mm to Female 3.5mm 1/8" Audio Adapter with 90 deg angle Can be connected to a miniature 2.5mm headphone jack on Phones to get a 3.5 mm Male output One application to connect adapter Audio/Mic to a DECT phone (or wireless handset) with a Speaker Conference phone