This is the mobile phone you've been searching for. The ClearSounds ClearDigital Amplified Cell Phone offers not only amplification to increase the loudness of the sound, it also offers frequency control. Frequency control allows you to adjust the tone (sometimes referred to as pitch) of the call. This creates both loud and clear sound. The simple design, large 1/2" buttons and large, bright backlit screen make every call a breeze. No more frustration with the complexities of today's smart phones. When you are looking for a simple phone that offers terrific sound quality, simple functionality and large buttons - the ClearDigital GSM Cell Phone is the answer. Unlocked for use with USA GSM carriers such as AT&T and T-Mobile. NOT compatible with CDMA carriers such as Sprint and Verizon