Precision measuring tools such as calipers measure dimensions of workpieces, parts, or features for a variety of applications including quality assurance inspections. Micrometers perform outside, inside, depth, or specialty measurements at a higher level of precision than calipers, other gauges, and hand tools. Indicator holders, magnetic bases, and stands are used for secure mounting. Height gauges measure and set height, step dimensions, and vertical distance. Pin plug and ring gauges perform pass/fail tolerance testing of specific diameters and threads. Surface roughness testers sample average and min./max. roughness of part surfaces for quality assurance and finishing applications. Thickness gauges measure thin materials such as sheet metal and plastic. Feeler gauges are inserted into gaps to determine width and are often used as shims. Inside diameter gauges such as bore gauges and telescoping gauges perform direct or indirect measurements.