A-B17100433YP-AI GRASS BAG, DOOROne New Aftermarket Replacement Grass Bag Door for Snapper, Simplicity, Murray, and Fits Briggs & Fits Stratton Yard Power Walk Behind Mowers This aftermarket replacement grass bag door fits 21 inch walk behind lawn mowers across the Snapper, Simplicity, Murray, and Fits Briggs & Fits Stratton Yard Power equipment families. The grass bag door secures the rear opening of the grass catcher assembly, keeping collected clippings contained during mowing