PRO-LINE Archival Quality Because PRO-LINE's specially formulated polypropylene has a physical density that is less than other sleeving materials, it is more pliable and gentle to your film. Strong and durable, PRO-LINE won't become brittle or abrade film. PRO-LINE sleeving is optically clear, color neutral, and has a unique anti-Newton ring surface that reduces distracting Newton rings as well as minimizing the actual surface area that is in contact with your film. Large Format Sleeving: PRO-LINE large format sleeves are made of premium 3 mil archival polypropylene and are available from 4"x5" to 20"x24" in clear, or clear with frosted back, with an open or sealed side flap