Fully Compatible: Works with 2 line or 4 line Land line phones corded or cordless - provides music / messages on hold on up to 2-Lines | Super Easy Connection: Preloaded USB Flash drive with over 50 mp3 files (including Holiday files) Plug and play - hours of royalty free music and standard thank you for holding messages -- Built-in speaker - Monitor the audio on the device directly via the built-in speaker - Place on a shelf or easily mount to any surface via built-in wall mount. | EASY Activation: uses Flash button on your phone - simply press Flash (or ON or Talk or Line) then Hold to place the call on Music/message on Hold - works on any regular telephone | SATISFACTION GUARANTEED: We provide technical support for customers 24/7, feel free to reach us by Email or Phone and we will gladly assist you at any time!. Product comes with 1 year parts & labor warranty, includes - Free Audio Music editor & Recorder software for PC (Windows 10+, 8, 7, Vista, XP) and Mac, 128MGB USB thumb drive preloaded with hours of royalty-free music, phone cord , wall mount screws, power adapter 110 / 220 VAC - 5VDC @2000mA and manual