Romabio BioGrip Micro is a universal mineral primer that is toxin-free and environmentally friendly. High-performing mineral primer made for extreme durability for interior and exterior surfaces. Ideal for Hardie Board/Cementitious Board/Concrete/CMU Block/ Portland or Gypsum Stucco/Painted Drywall/Painted Brick/Painted Stone/Unabsorbent Or Glossy Brick Breathable primer that can be used with acrylic painted surfaces. Excellent coverage of 300-375 ft2 per average gallon (after dilution). Easy to apply with brush, roller or sprayer. Hand crafted in Italy using 2,000 year old techniques and modern technology for a revolutionary product. Cradle to Cradle Certified, HPD, and A+ French VOC emissions, Romabio backs its marketing claims with 3rd party testing. Romabio products are “bio-logical,” manufactured with intelligence and care, and inspired our name: “Roma” for Rome, Italy, and “Bio” for organic and natural.