What is the difference between the grades of plywood

Plywood grades (E) (A). This is an elite plywood, which has not visible defects and deficiencies on the sheet surface. The random defects in the form of breaches of the textural drawings are allowed, but the presence of dark spots on the surface of the plywood (e) is unacceptable. There should be no knots and knot holes, minor brown veins, wormholes and other defects. The E grade plywood is virtually non-existent on the retail market, because it is normally used for the manufacture of laminated plywood.