IPA's Tire Comparator Type II, No. 9067,can compare tire diameter on "dualie" tires fast and consistently. The tool helps ensure fleets greater fuel economy and tire life by catching minute discrepancies in tire pairing. A 1/4" variance in tire size can cause the larger tire to support a far greater load. This results in not only accelerated tread wear and increased heating on the larger tire. The sliding tolerance gauge requires no measuring, guessing, or even visual inspection. Just hold it against the tire and slide across the treads for a quick pass/fail result every time. Made in the U.S.A.