Cat MD5150 tracked rock drill drills holes up to 6 inches in diameter. The carousel rod changer holds six rods and accommodates multiple lengths and diameters of drill steel. The rod changer is supported by a sturdy feed and heavy-duty 8-foot boom that extends to 11 feet for larger pattern coverage. Powered by a Tier 3 Cat C11 engine rated at 385 horsepower at 1,800 rpm.