Ultra-Tool's Series 650 Pollished Ground Carbide Cylinders feature the same world-class tungsten carbide substrate we use in all our finished cutting tools. Ultra-Grain has an excellent combination of high hardness & transverse rupture strength. Additionally, although cemented carbides typically feature poor corriosion resistance, our Series 650 offers industry leading specificatons for this characteristic as well. These cylinders, like all Ultra-Tool solid carbide products, are Shrink-Fit Ready (SFR).