Diamond Blades for Mongoose Decorative Concrete engraving saw. 4.0in x .250in and 4.0in x .375in widths are RCT (reduced core thickness) blades. This is necessary to safely operate on a Mongoose. Standard thick core blades will not properly mount on a Mongoose. The 4.0" x .080" discount blade is imported, and may have a shorter lifespan; all other blades are made in the USA.