The Pina Zangaro 11x8.5 Polypropylene Express Sheet Protectors are identical to Pina Zangaro's Polypropylene Sheets, but they have no black liner. Made in the USA of inert, unplasticized, heat resistant and chemically stable archival quality .0045 polypropylene, these sheets pass the PAT test and feature a non-stick finish to prevent adhesion to your artwork. The sheets are top-loading and are sold in packs of 10 in a protective metallic resealable bag.