Monterey Hardcore Pro Canvas Panels are made of medium-weight, all-purpose, sized and double-primed cotton canvas mounted with pH neutral non-yellowing permanent adhesive to engineered-wood rigid-core boards. The glue sizing is an important barrier to help prevent warping or mildew, and the vinyl backing makes the panel impervious to moisture, which keeps it flat. The archival, acid-free and pH balanced 1/8" thick panels work well for oils acrylics and alkyd paints. They are ready to paint and are ideal for plein air painting.