Dual RJ9 RJ11 WITH MUTE Headset Training Adapter - 5 Pack: Amazon.co.uk: Electronics & Photo
VoiceJoy Headset Adapter/Converter VoIP 2.5mm Headset to RJ9/RJ10 Plug ONLY for Cisco Phones,Cisco 794X 797X 796X 88XX 99XX Series : Amazon.co.uk: Electronics & Photo