Un-graduated machinist squares are ideal for positioning and ensuring straightness and squareness 4 Piece square set crafted from hardened spring steel Set includes: 2" Blade Length x 2" Base Length; 3" Blade Length x 2-1/2" Base Length; 4" Blade Length x 3" Base Length; 6" Blade Length x 4" Base Length Precision ground to ensure straightness and parallelism; working edges of each blade are lapped for accuracy Hardened spring steel blade is permanently secured to the base to ensure rigidity The SPI 13-634-1 Machinist Square Set includes 2", 3", 4" & 6" Blades. Manufactured to exacting specifications, hardened spring steel blades are permanently secured to each base to ensure rigidity. Each edge is precision ground to ensure straightness and parallelism. The working edges of each blade are lapped for accuracy.