The 21-inch curvilinear mower deck, designed for optimized airflow, is composed of heavy-duty steel to stand up to the most rugged conditions. The deck has been designed to produce an efficient path for grass clippings to pass into the bag or onto the ground when mulching. The efficient pathway improves bagging and mulching, preventing grass clippings from clogging. The HRN wheels offer excellent traction in a variety of mowing conditions. The large 8 inch wheels will tackle rough and tough conditions with ease and they will last and last.