Our Savannah Shutters are made with Premium Engineered Hardwood. High Density Fiberboard (HDF) is scientifically designed with cross grained hardwood fibers, blended together with industrial strength resins. The cross grained fibers and the resins work together to offset the movement that occurs in natural woods. Because natural wood expands and contracts in the direction of the grain, the cross fibers of the engineered woods stabilize one another, resulting in a product that is less susceptible to the effects of moisture and temperature change.