Gel highlighters feature SmearBlock gel technology that provides total smear protection across pen, marker and inkjet inks. Smear protection includes ballpoint, roller and gel pens. Gel highlighter works on all paper surfaces including glossy, rice (Bible pages), and vellum papers. Gel highlighter ink won't bleed through papers. Gel highlighter won't dry out if left uncapped. Sharpie Gel technology writes as long as a traditional pen-style highlighter. Gel stick conforms to your handwriting style so it's perfect for highlighting, writing, doodling and drawing. Simply twist bottom to advance gel stick. Gel highlighters are nonrefillable.