The Honeywell FE-R3T Microswitch Phototransistor Scanner is an optical sensor that combines a microswitch-style housing with a phototransistor to detect light signals. It is used in automation and control systems to sense object presence, position, or alignment by monitoring light interruption. The FE-R3T designation places it within Honeywell's line of optical sensing components, suitable for integration into control panels and machine wiring where a discrete opto-electronic switch is needed.
