Zultys ZIP 4x4, ZIP 4x5 , Pansasonic ,AT&T Cordless phones with 2.5mm jack. IF YOUR PHONE IS NOT ON THE LIST, PLEASE CONTACT US TO CHECK THE COMPATIBILITY. Grandstream GXP-2010, GXP-2020, GXP-2100, GXP-2110, GXP-2120, GXP-280, GXP-285,BT200,BT201, Zultys ZIP 4x4, ZIP 4x5 , Pansasonic ,AT&T Cordless phones with 2.5mm jack. Grandstream GXP-2010, GXP-2020, GXP-2100, GXP-2110, GXP-2120, GXP-280, GXP-285,BT200,BT201. [COMPATIBILITY] QD Bottom Adapter with 2.5mm jack is compatible with Ciso SPA Series, 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. [Features] Ergonomic curved headbands for comfort wearing with smooth click stop for adjustment and strong connection between headband and speaker body. [All day Comfort] Light weight, Very comfort, endurable and smart designed for office, contact center and home workers. Softy foam cushions is included. [WARRANTY] 3 years after purchased date. [ASP Circuit] Acoustic shock protection circuit on the speaker protect your hearing from unwanted peak noises on desk phones. Cut over 105dB and keep less 105dB level. [Ready to Use] Quick Disconnect (QD) to 2.5mm jack(3 poles-2 black bands) with IPD Headset allow easy connection to the 2.5mm headset jack of desk phones and cordless phones. Plug and play. [WIDEBAND AUDIO & NOISE CANCELLING MICROPHONE] IPD IPH-250 Single Ear, wired phone headset has a HD Wideband speaker to be clear sound and passive noise cancelling microphone make clearer conversation by reducing background noise.