2.5mm jack with QD adapter- 2ft cable with 1ft curly cord(extended to 10ft). Easily connect to headset with QD. *2.5mm jack is gold plated 3 poles. See moreZultys ZIP 4x4, ZIP 4x5 , Pansasonic ,AT&T Cordless phones with 2.5mm jack. Polycom IP 320,321,330 and Other Cordless phones with 2,5mm Standard Headset Port.(3 poles with 2 black bands), No Smart phone use.Grandstream GXP-2010, GXP-2020, GXP-2100, GXP-2110, GXP-2120, GXP-280, GXP-285,BT200,BT201. Cisco All SPA Models SPA303, 501G, 502G, 504G, 508G, 509G, 525G 512G 514G,525G,SPA921, SPA922, SPA941, SPA942, SPA962, Polycom IP320, IP321, IP330, IP331, SoundPoint Pro SE-220 SE-225. *2.5 mm jack with QD adapter and bottom culry cord to connect all of IPD headsets. *Cable length is a 2ft cable with 1ft curly cord( extended to be 10ft). Directly connects to a 2.5mm headset jack on most landline and business phones. Very sturdy and tensil cable including Kevlar fabric is used. * Only Plantronics style QD and any IPD headsets are compatible. Not available with Jabra QD.