912CS Canvas Tarp 9′ x 12′ 20 oz. / Sq. Yard After Treatment w/ Gromment 3′ on Center Tarps are made of cotton duck, 12 oz. per sq yd. before treatment, 20 oz. per sq. yd. after treatment. Features include: double stitched, mildew-retardant, water-repellent, rust-resistant grommets spaced three feet apart. Custom sizes are available on special orders.