Designed to accurately measure lifter bore diameter and bore roundnessIncludes ball sizes 0.8430'', 0.8435'', 0.8440'', and 0.8450''Made in the USAFeuling® recommends a lifter to lifter bore clearance of 0.001'' - 0.0015'' for optimum lifter performance.Fits: EVO '84-'99, Twin Cam '99-'17 and M8 '17-'24 lifter bores.