1 Pack(100) Sheet Music Sleeve 9-3/8 x 12-1/4 3 mil - Store your DIGESTS, PAPERBACKS and PULPS in our POLY BAGS and protect them from dust, dirt, finger oils and other airborne pollutants. Our bags hold size and thickness tolerances and come in printed outer bags for easy product identification. We stock paperback and digest bags made out of polyethylene and polypropylene. Both of these materials have passed the Photo Activity Test (P.A.T.) certifying that they are safe for long-term storage.