We're often asked to provide roughness tester standards with non-standard values for calibration of surface roughness testers, also known as profilometers. Most instruments sold by Mahr-Federal, Fowler, Mitutoyo, Phase II, Brown & Sharpe and others include a calibration specimen (typically provided with a NIST traceable certificate) in the 119 Ra microinch range (3 um), which is the industry standard. Set your instrument to this specimen and it is assumed your tester is calibrated properly.
But we offer a couple of better options, the GAR Dual and Triple-patch PRS-3 series (Precision Roughness Standards). Available with either a short-form or long-form NIST certificate (standards with long-form certs are also individually serialized), the dual-patch standard adds a second patch for checking wear on the diamond stylus while the triple-patch standard adds another patch for checking linearity - this is the roughness standard I generally recommend to our clients, regardless of the brand of the tester. You'll find information on these items in the surface finish section of our on-line store.