Home / Detectors / Aspirating Smoke Detectors / System Sensor 1251 System Sensor 1251 Ionization Smoke Detector Request a Quote This product is already on your Quote Request Browse your Quote Request Material ObsoleteBrand: System Sensor FireAlarm.com Part #: 4891 Category: Aspirating Smoke Detectors Manufacturer Part #: 1251 Specifications Information Weight 1.00 lbs Production Status Material Obsolete Brand System Sensor Product Notes Replacement: 2151