My classroom is somewhat large. I could badly hear the bell across the room when the kids were quiet. I purchase a mor expensive doorbell from Home Depot that works perfectly.
AVANTEK D-3W Waterproof Wireless Doorbell Kit With 2 Plug-In Receivers Operating At Over 1300 Feet, 52 CD Quality Melodies, LED Flash, And Long Range
34 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
Universal 24V 40VA Thermostat / Doorbell Transformer: Compatible with Honeywell, Nest, Sensi, Ecobee, Nest Hello, and Ring Doorbells
43 Review
STARPOINT LR Wireless Doorbell Chime With Expandable Add-On Receiver Plugin - Long Range Multi-Unit Alert System, White
37 Review
π‘ High-Quality Advance ICN-4P32-SC Electronic Fluorescent Ballast: Ideal for 4 Lamps, 32W T8, 120/277V
3 Review
π‘ GE Lighting 72266 Fluorescent T8 Ballast 2 or 1 F32T8 Lamps - UltraMax Electronic, Instant Start, Multi-Volt (120/277V)
3 Review
π‘ Enhance Lighting Efficiency with Sunpark SL26T Electronic Circline Ballast (2)
3 Review
π‘ Fulham Lighting WH7-120-L Workhorse 7 Versatile Fluorescent Lamp Ballast - 20 Count Silver
3 Review