These are replacement blades for our detail hand scraper. Made of heavy-duty 5/64" thick carbide, they can be rotated to use a fresh edge when one side dulls. The square and triangular blades have radiused corners to avoid gouging your work. The square blade is just under 5/8" on each side, the triangular blade just under 7/8" on each side, and the round blade just over 5/8" in diameter.