Features For use on 5330/5340/5360 IP Phones. Includes: 50005521 Cordless Accessories Module (NA DECT) 50005522 Cordless Headset w/Charging Cradle (NA DECT) Requires: 3300 ICP, Release 8.0, UR1 SX-200 ICP, Release 4.0 (UR3) Not Supported on SIP Phones.