Zig Posterman Waterproof BIGGIE 50mm Fluorescent Yellow Paint Markers - Box of 6 Opaque, lightfast, odorless, and waterproof, providing the look and feel of chalk. Works great on glass, plastic, metal, wood, stone and more. Valve-action 50mm wide tip for writing broad or fine lines. Perfect for whiteboards, chalkboards, signs, windows, boards and more. Price and shipping is for a box of six (6) fluorescent yellow markers.