
If you own one of these systems and want to add another ringer this does the job. You do need to pair it with you doorbell units.

Optimize Viewing With CAVN Black Angle Mount For Ring Video Doorbell 1 2 3 4 - Adjustable 30 To 55 Degree Angle
30 Review

Universal 24V 40VA Thermostat / Doorbell Transformer: Compatible with Honeywell, Nest, Sensi, Ecobee, Nest Hello, and Ring Doorbells
43 Review

Wireless Doorbell Chime - AVANTEK Mini Waterproof, 1000 Feet Range, 52 Melodies & 5 Volume Levels With LED Flash
31 Review

Wireless Doorbell, PHYSEN Waterproof Door Bell Chime Kit Operating At 1300-Ft Range 58 Adjustable Melodies 5 Volume Levels & LED Flash, Doorbell Alarm For Home/Classroom, 2 Push Buttons+4 Receivers
34 Review

π Robertson 2P20132 Quik-Pak: 10 Fluorescent eBallasts for 2 F40T12 Linear Lamps, Preheat Rapid Start, 120Vac, 50-60Hz, Normal Ballast Factor, NPF, Model RSW234T12120 /A (Crosses to RSW240T12120 /B)
4 Review

π‘ High-Quality Advance ICN-4P32-SC Electronic Fluorescent Ballast: Ideal for 4 Lamps, 32W T8, 120/277V
3 Review

β‘οΈ Sunpark LC-12014T (1) FC12T9 32W Circline (1) 2D 38W (1) FC16T9 40W Circline (1) FC9T9 30W Circline Lamp Compact Electronic Fluorescent Ballast with Circline Lamp Plug 120V
7 Review

π‘ Electronic FL Ballast ICN-4P32-N (Formerly ICN-4P32-SC) for 3-4 F32T8 F40T8 F17T8 Lamps, 120V/277V Compatibility
5 Review