Audicom Standard 3.5mm Smartphone Headset Adapter Cable Converter to 2.5mm Jack Telephone Panasonic KX-NT136 KX-NT343 KX-NT346 KX-NT366 IP and Cordless Phones with 2.5mm Headset Jack (H35-25D) Convert 3.5mm Smartphone Headset plug to 2.5mm jack telephone port. NOT COMPATIBLE WITH IPHONE HEADSET. Smartphone Headset 3.5mm Female to 2.5mm Male Save money by buying a smartphone headset, or using your existing one with your phone's jack. All functions on headset and phone would function same. Easy Setup, Plug and Play Only works for some specific phones. Please see compatible phone models list in description below