Heiman Carbon Monoxide Detectors, Low-Level Digital Display CO Alarm 3 Pack

10 Year Sealed Lithium Battery, No Replacement Needed — Equipped with a built-in 10-Year CR-2/3AZ lithium battery, this carbon monoxide alarm uses a sealed, non-removable battery design. **This unit has no pull tab**: Initial activation requires inserting the included bracket into the back groove and pushing upward. Once started, this CO alarm runs a 100-second warm-up cycle automatically, then enters standby monitoring mode. It cannot be manually turned off and runs until low-battery or end-of-life alert triggers.
UL 2034 5th Edition Certified & CSFM Approved — Meets strict UL 2034 5th Edition sensitivity and performance standards, and is CSFM approved for residential carbon monoxide alarm applications, compliant with NFPA installation codes.This CO alarm provides reliable protection for homes, rental properties and residential spaces. **NOT for use in garages, workshops, or directly under vehicle mufflers/exhaust pipes**. Operating temperature range: 40°F to 100°F (4.4°C to 37.8°C); performance will be compromised outside this range.
Real-Time LCD Display + Graded Low Level CO Early Warning System — This carbon monoxide detector features a clear digital screen showing live CO readings starting at 20ppm (20–999ppm measuring range), so you can gauge hazard severity at a glance. The co alarm delivers multi-stage alert system: 30ppm early warning for slow low-level buildup, a loud 85dB danger alarm, and 12-hour alarm memory to alert you of missed CO events when you return home.
Dual Installation Modes | Tabletop & Wall Mount — No wiring or electrician needed for this co detector. Place directly on any flat surface for instant use, or wall-mount with the included full hardware kit. It auto-powers on after a 100-second warm-up with zero extra setup.
Ultra-Compact & Portable for Home & Travel — Measuring just 4.09″ L × 2.89″ H × 1.43″ W, and only 4.37 oz, this lightweight CO detector works perfectly for everyday home use and on-the-go protection. Bring reliable CO safety to hotels, vacation rentals, RVs, cabins and more.
One-Touch Hush & Simple Weekly Self-Test — The single Test/Hush button silences nuisance CO alarms (4 minutes), low-battery chirps (12 hours) and end-of-life alerts (48 hours), while uninterrupted CO monitoring remains active. Use the button for quick weekly self-tests to confirm proper operation.
All-Source CO Detection for Home, RV & Travel — Reliably detects carbon monoxide from fuel-burning sources, including gas furnaces, water heaters, fireplaces, car exhaust, clothes dryers and kitchen stoves. Compact and portable for flexible use at home, in RVs, campers, and during travel. Ideal for bedrooms, hallways, living rooms, basements, garages and multiple floors of your home.