The Krown TA005 telephone ring signaler has a loud, 120dB amplified audible ringer and a bright strobe light that flashes when there is an incoming phone call. It connects between the telephone and wall phone line. Features: Loud ringer up to 120dB Audible ringer operated by telephone line (included) Built-in dual phone jacks Strobe light with on/off switch operated by AC adapter (included) Battery backup (three AA batteries not included)