For Drawing Size 48 x 36". Folders are made of red wallet stock with mylar reinforced handles for extra strength. Each folder can hold 50 drawings for active filing. For inactive/archival storage, depending on the material, the capacity increases to 100 drawings per folder (based on .003" vellum). Storing more drawings results in a loss of operation convenience. Folders are slightly waxed on the outside with paraffin wax so they smoothly glide back inside the pocket.