Dacproofer #300. Fabric primer coating (blue in color) used after cloth is tautened. Coating penetrates the weave and bonds to itself to the backside of the cloth completely surrounding and encapsulating each individual strand. This is the first coat applied to the fabric after ironing. Reduce with #132 retarder thinner only for proper dry time. May be applied with short nap roller. Available in gallon and 5 gallon sizes. Thin 1:1.