Can be used as a mulcher even without the mulch plate. If used with the bagger only about 1/3 of the clippings go in the bag, the rest are mulched back in the grass and you wont see them (unless the grass is very high). Use only in sets of 3. Can be used to replace the following blade numbers: 145708, 152446, 159705, 163819, 170698, and 176084.