Dasqua 81 Piece Grade 1 Gage Block Set ~ Made of high-grade steel that has been carefully hardened and stress-relieved. ~ Well lapped measuring faces for high accuracy. ~ Edges slightly beveled for protection. ~ Strictly made in accordance with DIN861. ~ All measuring faces are lapped. ~ Mirror-polished. ~ Provides maximum durability under the most demanding conditions. ~ Steel blocks are hardened to 65HRC.