INSIZE V-Block Set Sold as 2 Matching V-Blocks per Set, made of alloy steel, hardened to HRC60+2. Hold cylindrical workpieces for inspection and machining. Specifications include... Size: 1.0" x 0.8" x 0.8" Holding Range: 0.12" - 0.79" Parallelism of both V-Grooves to top and bottom sides: 118µin Squareness of both V-Grooves to front and back sides: 118µin