4" masonry blade. Provides faster rate of cut at constant depth with 30 times the life of bonded abrasive blades. For cutting concrete, brick, and other masonry material. Max RPM 8500. Blade Type: Masonry, Blade Diameter: 4", Arbor Size: 5/8", 7/8", Maximum Speed: 8500 RPM, Pkg Qty: 1, Package Type: Card No. DW4724B: Blade Type: Masonry, Blade Diameter: 4", Arbor Size: 5/8", 7/8", Maximum Speed: 8500 RPM No. DW4725: Blade Type: Masonry, Blade Diameter: 4-1/2", Arbor Size: 7/8", Maximum Speed: 8500 RPM, Pkg Qty: 1, Package Type: Card No. DW4725B: Blade Type: Masonry, Blade Diameter: 4-1/2", Arbor Size: 7/8", Maximum Speed: 8500 RPM