The document discusses Gagemaker's PG-6000 and RG-7000 series gauges which measure the diameters of internal and external threads respectively. It also discusses their Pitch Diameter inspection gauges PD-6000 and PD-8000 series which measure pitch diameters of internal and external threads. The gauges must be preset to a nominal predetermined dimension using various measurement tools. It provides details on the gauges, their code numbers, description and measurement ranges.