The Clarity Professional XL40D is a large button amplifier telephone designed for use by people who are hard of hearing or have low vision. This phone amplifies incoming sound up to 50 decibels (dB), amplifies outgoing speech up to 15 dB, and offers four adjustable ringer levels up to 90 dB. It also has large backlit buttons with white numbers on a dark background. The phone features 12 speed dial buttons; bright visual ringer with voicemail indicator; Digital Clarity Power technology that makes words louder, clearer and easy to understand; and ClarityLogic technology which allows a customer service representative to see inside the user’s phone and remotely make adjustments. The phone can be desk- or wall-mounted, has a jack (2.5 or 3.5 millimeters) for assistive listening devices or headset, and comes with dual power backup which lets the user make calls when the power is out. OPTIONS: Bed Shaker and hearing aid compatible headsets. POWER: The base is powered by a 9 volt 500 mA DC adapter; dual power backup uses 4 AA alkaline batteries (not included). DIMENSIONS (DxWxH): The base is 9.5 x 7 x 3.25 inches. WEIGHT: 2.52 pounds. WARRANTY: One year limited warranty.