Arista 24-1433 Amplified Telephone Ringer/Flasher Landline Amplified ringer with flasher, providing both visual and amplified audio/ringer cues. Perfect for noisy areas, garages, warehouses, and the hearing impaired. Use when the normal ringer on your analog modular phone alone is insufficient. Easy connect, no batteries required. Wall-mount slot on back. Installation instructions included on package. Additional phone line cord needed (not included). NOT for use with digital/business phone systems (analog phone lines only).