PI TAPE 2" to 12" Range Periphery Tape Measure Tape has a fixed reading that does not require periodic adjustment Quick, accurate, direct measurement of the diameter by measuring the circumference only. Body width: 1/2". Thickness: .010", .007". Gage member: 1/4". Accuracy: .001" Standard English reading tapes read to .001" diameter. All graduations and numerals are engraved and acid etched on a ground surface.