The Panasonic KX-NT303 is the 12-button add-on module that expands the KX-NT343 and KX-NT346 IP telephones to 12 programmable keys. And with the KX-DT301B USB module, you can easily connect your phone to your PC and use the many advantages of computer telephony integration (CTI). IP Add-On Module Features: Compatible with the KX-TDA, KX-TDE, and KX-NCP IP PBX Panasonic Communications Systems so its ideal for companies with geographically diverse office locations and helps connect employees and customers IP-PT to LAN Connection Multi-Angle Tilt Body provides 2 angles to allow for the most comfortable positioning Flexible Outside (CO) Line Buttons: 12 keys Green and Red Illumination Dual Color LED based on line status Wall Mountable Only one can be added per telephone Dimensions: 5.91" H x 10.63" W x 9.06" D Available in Black or White Color