FG50 Alkali Resistent Fiberglass Mesh Reinforcing FG50 is an alkali resistent fiberglass mesh for reinforcing concrete products. When used in conjunction with Z Clips and Z Liqui -Crete, it is the perfect reinforcement for cast-in-place concrete countertops. Comes on 2' wide roll - perfect for countertops. 50' x 2' on a roll. 100 sq . ft.