Does just what it says, mulches the blades of grass to a finer/smaller pieces. I like to bag my clippings. I looked at the clippings some are about a 1/2 to 1/4" or less. This was after I let the grass grow too long about 4-6", Life got in the way. In full disclaimer, I use double blades (4, 2 on each side) on my 10 year old Cup Cadet LT 1018. One high lift blade, one mulcher.