Elderly friendly telephone with big buttons, which is powered by the phone line, please install 3*AA (Not Included) battery to keep the number in the phone even when the power goes out. Multi-function - Compatible with DTMF/FSK/ETSI. And 16 Digit LCD/Last Number Redial/61 Incoming Calls Memory/16 Outgoing memory, 3 One touch memories,1 Alarm clock and Music on Hold function, 21 kinds of ringing tones for selection, etc. Ringtone Level - You can adjust the ringtone level using the "Switch" on the back of the phone, switch to "l" for low volume, "h" for high volume. Lightweight & Simplify Design - The font on the button is clearly printed and easy for the elderly to identify. Lightweight telephone that can be placed on any surfaces. Wide Application - Compact size and convenience design, suitable for family home, hotel, etc.