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. Clip-on stones and wipers are easily changed in a few seconds, stones are available in five grits. Use with heavy-duty 1/2" drill Engine Cylinder Hone. Best by Far - Yet Competitively Priced. Standard range is 3" to 4 1/4". Big range is 2 3/4" - 10 1/4" with additional rack sets and stone sets. Universal joint action makes grinding of back cylinder easy. Cylinder hone body with 1 set of 15540 standard range rack (range is 3" - 4 1/4". 1 Set each of 15500 coarse stones and 15510 medium stones, cleaning brush and dressing paddle in a sturdy storage case. Another quality product brought to you by Lisle.