Yard-Man Series 12A-979-401 is a walk-behind lawn mower designed for residential use. It is powered by an internal combustion engine and features a 21-inch cutting deck. The mower has a variety of features that make it easy to use, including a self-propelled drive system, a mulching feature, and a bagging system.

The self-propelled drive system makes it easy to mow large areas of grass without having to push the mower manually. The mulching feature allows the mower to cut grass clippings into small pieces and return them to the lawn, which helps to fertilize the grass and reduce the need for chemical fertilizers. The bagging system allows the mower to collect grass clippings in a bag, which can then be emptied into a compost pile or trash can.