The Simplicity 7100640 is a genuine 21-inch mower blade designed for optimal cutting performance. This high-quality blade is compatible with a wide range of equipment from brands including Simplicity, Snapper, Ferris, Briggs & Stratton, Murray, Craftsman, Husqvarna, and Ariens. Featuring a durable construction, it ensures a clean cut and extended lifespan for your lawn and garden machinery. It has a length of 533.4 mm, a width of 57.15 mm, a 23.8 mm center hole, and two 9.525 mm outer holes spaced 63.5 mm apart.