Amplifies Most Corded PhonesAmplifies incoming voice up to 40dB
Tone control to enhance clarity
Connects easily between handset cord and phone base
Universal dial provides compatibility on 99% of corded telephones including VOIP
Operates on one 9-volt battery (not included)
One-year manufacturer's warranty
Note: In-line amplifiers are not compatible with Trimline, Princess-style or cordless phones where dial key pad is in the handset.