Silent Knight by Honeywell
Farenhyt IDP-FIRE-CO detector's sounder base features different tones for fire and carbon monoxide alarms. Four separate sensing elements look for smoke, carbon monoxide, light/flame and heat, while minimizing nuisance alarms.
SC Johnson Professional: Alcare Extra with OPTIDOSE
Horton Automatics: BH Slider
Kimball International: Shore
Protimeter: Aquant
Sensaphone: Sentinel PRO