Gamewell-Fci MCS-COF3-IVeBay The Gamewell FCI MCS COF3 IV is a plug in device that detects fire and carbon monoxide (CO). It detects smoke, CO, light flame, and heat using four sensing elements. The MCS COF3 IV has a photoelectric sensing chamber, a CO sensor, a 135F (57. 2C) fixed temperature heat detector, and infrared (IR) sensors. It also has sophisticated algorithms that use all four sensor types to create a detection strategy. This strategy provides enhanced