Fowler 52-381-005 Flexible Steel Inch/Metric Series Rule with Satin Chrome Finish, 1mm and 0.5mm / 10ths and 50ths Graduation Interval, 150mm L x 13mm W x 0.4mm Thick

The Fowler 52-381-005 Inch/Metric Satin Chrome Steel Rule is a 150 mm rule made of hardened, tempered steel with a non-glare satin chrome finish. It has inch graduations on the front, 10 mm graduations on the back, and microfine subdivisions for 1/10", 1/50", 1 mm, and .5 mm. This flexible rule is 150 mm long, 13 mm wide, and 0.4 mm thick. It is rust- and wear-resistant and meets federal accuracy specifications. Applications include measuring depths and widths of grooves and recesses.

Rules are devices used to measure distances, or to rule straight lines. Rules have markings at specified intervals (also called graduations), as opposed to straight edges, which lack graduations and are used solely to draw a straight line. Nearly all rules are straight edges, except for rounded rules used to measure circles and arcs of angles in geometry applications. Rules can vary from high-quality steel instruments used by machinists; to retractable rules (also called tape measures) used in carpentry and for home-use; to simple wooden or plastic rules used in primary and secondary schools.

The Fred V. Fowler Company manufactures inspection and measurement instruments such as electronic indicators, calipers, bore gages, and digital scales. The company, founded in 1946, is headquartered in Newton, MA.