INSIZE V-Block Set Sold as 2 Matching V-Blocks per Set, made of alloy steel, hardened to HRC60+2. Hold cylindrical or rectangular workpieces for inspection and machining. Specifications include... Size: 2.6" x 2.8" x 2.0" Cylindrical Holding Range: 0.20" - 1.97" Rectangular Holding < 1.38" Parallelism of V-Groove to top, bottom, left, right sides: 197µin Squareness of V-Groove to top, bottom, left, right sides: 197µin