IO‑Link Signalling Lights are classified primarily by illumination technology. The dominant LED type accounts for roughly 70 % of total revenue, driven by its low power consumption, long lifespan, and compatibility with the digital communication protocol of IO‑Link. OLED devices represent a niche (~12 %) that offers flexible form factors and uniform light distribution, appealing to OEMs seeking aesthetic integration. Fiber‑optic signalling lights, contributing about 8 % of market value, are employed where electromagnetic immunity is critical, such as in hazardous zones. A smaller share (~5 %) is held by traditional incandescent lamps, retained in legacy retrofits due to lower upfront cost despite higher energy use. Emerging laser‑based indicators, still under 5 % of the market, provide high‑intensity point‑source illumination for precise status feedback in high‑speed machinery. Collectively, these type segments shape the overall market size by aligning product characteristics with cost, reliability, and regulatory requirements across end‑use environments.