The Brown & Sharpe 598-291-500 Sine Bar Riser Set is made from hardened and precision ground steel to help reduce wear and corrosion, and is supplied with a back plate to provide extra support. The set features 1” body size, 5” distance between centers of rolls to within .0003”, and top parallel to bottom of rolls to within .0002”. The set comes with a “declaration of conformity” that the tool is manufactured within the stated tolerance.Sine bar risers are commonly used in machine setups to quickly measure angles.Brown & Sharpe was founded in 1833, had a major part in setting industrial standards in the United States, and has given its name to several standards, including a tool spindle taper, a worm threadform, and others. Brown & Sharpe was acquired by Hexagon Metrology in 2001, and has since focused on precision measuring equipment and metrology hand tools. The Brown & Sharpe line of coordinate measuring machines (CMMs), optical measuring systems, benchtop measuring machines, and precision hand tools offer consistent, high-quality design, construction, and performance. Brown & Sharpe has manufacturing facilities in North America, Switzerland, and China.