The PRD-420-B1 from RIKO is an ultra-flexible "anti-bending" fiber-optic sensor head designed for tight spaces, high-flex routing, and applications where standard fibre heads might suffer from breakage. It has a small diameter fibre (OD ≈ Ø1.25 mm) and a very small bending radius (R15 mm), making it ideal for use in confined automation equipment, moving parts, robotics and other compact sensing environments.