X-ray Marking Tape Roll 50mm x 7.5mX ray Marking Tape Roll economical and eco friendly. Grey marking area (rather than black) makes the tape easier to read, meaning fewer opportunities for error. Larger adhesive area on the overlapping tape improves adhesion to the film cassette. Tape formulation is completely lead free, keeping toxic heavy metals out of the waste stream. The tape system features holder blockers in four different densities for various exposure levels.