Cole-Parmer X-Ray Film Cassette, Aluminum, 5X7". Get the results you need at an affordable price-compare to name brand blue-sensitive, double-emulsion film for performance and value.Ideal for western blotting, DNA sequencing gels, chemiluminescent probes, gel shift analysis, and commonly used radioisotopes (32P, 125I)Double emulsion film gives you sharp contrast and exemplary resolution for DNA sequencingFilm is single-sided for exceptional clarity and low background.