Permanent Dura-Ink 25 Chisel Tip Marker. Contains low halogens. Ink formulated for industrial strength usage. Extra large ink supply for greater mileage. Environmentally friendly. Thin Side: 1/8, Thick Side: 1/4. Ergonomic design for extended use. Ink formulated for industrial strength usage, Smear-resistant, water-resistant, fast-drying, Long mileage, economical - Environmentally Friendly