Used on Craftsman, Poulan, Husqvarna, Wizard 42 inch decks. 21" long, 2 1/2" wide, 5 point star hole, .187" thick. (OEM blade is about .134" thick)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 as pairs.