Shop Honeywell Home Wireless Heat Detectors at GeoArm Security. Browse 5800-Series (345 MHz) and PROSiX encrypted sensors designed to detect rapidly rising or dangerously high temperatures in residential and commercial properties. These life-safety devices alert the connected alarm system when abnormal heat conditions are detected, helping provide an early warning of a potential fire. Honeywell-Compatible security systems support GeoArm 24/7 professional UL-listed central station monitoring or DIY self-monitoring with no long-term contract.