Made of carbon steel and fully austempered. 1 per card. No. AEB-159: 7/16'' square or 1/2'' round center hole, 9'' x 2'' straight cut, sharpened on 2 sides, fits King-O-Lawn, Sears/Craftsman, Lawn-Boy, Western Tool, McLane, Power Trim, Ruhman, and Western Auto No. AEB-410: 5/8'' center hole, 9'' x 2-1/2'', fits MTD/Yard-Man No. AEB-411: 1/2'' center hole, 9'' x 2'' straight cut, unsharpened, fits McLane No. AEB-511: 7/16'' round center hole, 7-1/2'' x 1-1/2'' straight cut, not sharpened, fits Black & Decker model No. 82240, OEM model No. 82-024 No. AEB-520: 7-1/2'' x 1-1/2'' x 0.09 steel edger blade with two 1/4'' round holes, fits Paramount, Roto Shear model No. 800, 700PM, and 700DM, and Sears/Craftsman model No. 85724, 85792, and 85795, tools required: Adjustable wrench