Micrometer head assures accuracy in feeding. Expands quickly to cylinder size with fast action rack and pinion. Bottom guard plate helps prevent stones from accidentally hitting the crankshaft. Universal joint action makes grinding of back cylinder easy. Clip-on stones and wipers are easily changed in a few seconds. Stones are available in five grits. Use with heavy-duty 1/2 inches drill. Standard range 3 inches to 4-1/4 inches. Big range (2-3/4 inches – 10-1/4 inches) with additional rack sets and stone sets. Long 5 inches stones cut faster, more accurately. Includes the following: Cylinder hone body with 1 set of 15540 standard range rack (range is 3 inches to 4-1/4 inches). 1 set each of 15500 coarse stones and 15510 medium stones, cleaning brush and dressing paddle in a sturdy storage case.