Premium Marine Grade G2S A-B Fir Plywood 4-ft x 8-ftPremium Marine Grade Fir Plywood (A B Grade) When the environment is demanding and structural integrity is non negotiable, our Marine Grade Douglas Fir Plywood stands as the industry standard. This isn't your average hardware store sheet; its a high performance substrate engineered to withstand consistent moisture and heavy stress. Why Marine Grade? Unlike standard exterior plywood, Marine Grade Fir is manufactured with zero internal Voids. No Hidden