Cryogenic Marker SetNalgene Cryoware Cryogenic Marker Set Cryo pens for writing on cryo tags, visotubes goblets, vials and other devices that will be stored in liquid nitrogen. Pens can permanently mark cloth, cardboard and plastic Red, green, blue and black ink will not fade at ultra low LN2 temperature Smudge proof Extra fine point pens available in black or a pack of four colors; red, green, blue and black. Specifications: Mfr. No. 6313 0020 Cryogenic Marker Set. Cryo