Prime-A-Seal Spray Primer is a professional grade primer designed to promote superior adhesion of MFM self-adhering products. Compatible substrates include old dry roofing, felts, asphalt, plywood, OSB, weathered metal and masonry surfaces. Allow Prime-A-Seal Spray Primer to dry to the touch before application of the membrane. Made in the USA. Black finish. Meets ASTM D 41 specifications. Not compatible with EPDM rubber.