The Omron E3FC-DN13 2M is a tubular U-shaped double-ended fluorescein particle sensor from the E3FC series. It is designed to detect fluorescent particles that emit in response to ultraviolet radiation. It can be used for various applications including level, liquid flow, and presence/absence detection. It has a compact and durable construction, with a detection range of up to 2 meters. It is well-suited for detecting particles or liquid levels in harsh, dusty environments or in systems subject to frequent vibration.