Never worry about smearing your notes again. These Mojini Single Ended Highlighters use a special ink formula that binds with water-based ink, such as gel or rollerball ink, to prevent smudging when highlighting over written notes. Soft, chisel tip flexes to make perfect contact with the page, giving you neat, 3.5mm to 4mm wide lines without having to hold the highlighter at the perfect angle. Highlighters also work great on curved surfaces like the pages of a textbook.