ClearSounds WIL95 Portable Telephone Amplifier with Volume Control and Modular Connector Phone Compatibility - White HIGHLY COMPATIBLE - No need to replace your existing telephone. Universal compatibility dial provides compatibility on 99 percent of telephones with the dial pad located on the telephone base. EASY ADJUSTMENT - Separate volume and tone controls with slider movement for easy adjustment SOUND CLARIFYING TECHNOLOGY - UltraClear Sound-Clarifying technology allows you to "shape" sound to match your hearing needs MAXIMUM AMPLIFICATION - Volume control and boost button up to 40 dB gain (30 dB adjustable amplification with the slider controls plus a 10 dB 'Boost' button for occasional added amplification) Powered by AC adapter (included) Powered by AC adapter (included)