Sharpie

Sharpie Markers, Pencils and Pens are standard tools on television and film sets for a wide range of uses, such as marking film leader, labeling props and equipment, and creating temporary "spike" marks for actor positions.
Their quick-drying, permanent, and water-resistant ink makes them ideal for marking surfaces like film, tape, gaffers tape, and various materials like plastic and glass, while their durable tips resist flattening and fraying.