The S-Series uses Non-dispersive Infrared, (NDIR), to detect chemical changes in low concentrations that could be potentially harmful or even catastrophic. The S-Series detects CO, CO2, Hydrocarbons, Gas, and many other chemicals indicative of smoke, fire, and gas leaks. The Series will offer the first of its kind portable device, the SP4, that can travel with you adding that extra piece of mind. The SP4 is designed to enhance current smoke alarms and detects smoke, fire, and gas much sooner than competing device.