Instantly convert your ordinary landline phone into an amplified phone and enjoy crystal clear calls you can actually hear and understand simply connect amplifier between your handset cord and base features onoff button adjustable volume and battery low indicator suitable for standard and electronic phones measures 2 x 2 x 1onoff buttonadjustable volumebattery low indicatorsuitable for standard and electronic phonesmeasures 2 x 2 x 1requires 2 x aaa batteries not included