The Mighty Marker IM-31 Ink-Tag Marker is the professional's choice for marking polyurethane tags, especially cattle ear tags, with bold, highly visible, and weather-resistant ink. Its formulation is built for longevity—resisting fading, abrasion, and exposure to sunlight or extreme weather conditions for up to 10 years outdoors. Equipped with a 4.0mm chisel tip, the IM-31 delivers clean, legible marks ideal for high-visibility identification. Its valve action mechanism prevents dry-out and ensures smooth ink flow—even if the cap is left off during use. With a 10ml ink reservoir, this marker is engineered for extended use on farms, ranches, and industrial environments where reliability matters most. Proudly made in the USA, the IM-31 is trusted by agricultural professionals who need durable, no-compromise performance in demanding conditions.