The steel go (+) plug gage is a class ZZ metric gage for calibrating measuring equipment and gage parts. A certificate of accuracy traceable to National Institute of Standards and Technology (NIST) is available for each gage, and each pin is marked with its size and direction of tolerance in sizes over .060”. Each gage is sealed in a volatile corrosion inhibitor (VCI) bag and packaged with a rust preventative. All gages are made of cold-stabilized tool steel 60/62 Rockwell c (Rc), measure 2” long, are within .00001” round (per ASME B89.1.5), and have at least a 10-microinch finish for a smooth finish. Sizes are available from .20 mm to 25.50 mm in increments of .02 mm, with a tolerance of -.005 mm for longer wear. Plug gages are precision-ground cylindrical steel plugs used to measure the diameter and depth of drilled or machined holes. They are available in different classes, based on acceptable tolerance (allowed deviation from the stated size). Standard tolerances and classes for cylindrical gages up to .825” are as follows: Class XX (.00002" or .0005 mm), Class X (.00004" or .0010 mm), Class Y (.00007" or .0018 mm), Class Z (.0001" or .0025mm), and Class ZZ (.0002" or .0050 mm). For gages with a wider diameter, tolerance gradually increases for each class. Vermont Precision Tools manufactures precision round and ground pins, perforators, and special punches. The company, founded in 1968 and headquartered in Swanton, VT, formed division in 1980 to manufacture fixed limit gages. It meets International Organization for Standardization (ISO) 9001:2000 standards.