The KEYENCE FU-66 is a high-precision fiber optic sensor head designed for stable detection performance in compact automation and inspection systems. Featuring an M4 size and a parallel detection layout, it ensures accurate sensing alignment and reliable signal consistency in confined or high-speed environments. The FU-66 comes with a 2 m pre-cut fiber length and a fiber diameter of ø1.3×2, allowing flexible installation and easy integration with a wide range of fiber amplifiers. With an approximate weight of 10 g, this lightweight yet durable sensor head is optimized for applications requiring precise object detection and space-efficient mounting. The KEYENCE FU-66 could be utilized in North America, Europe, Asia, and worldwide facilities that demand compact, high-performance fiber optic sensing solutions.