Specifically designed for use at ultra-low temperatures. Durable, cloth labels adhere to plastic and cardboard cryogenic storage boxes. Will not peel or shrink. Accepts ball point pen. Label dimensions: 1 x 2”. Twenty labels per sheet. Permanent markers are ideal for Cryoware labels. Smudge-proof, extra fine point pens for marking cardboard and polycarbonate. Marker set comes in 4 colors.