Includes 1 commercial Mulching Blade For 21 John Deere. Replaces OEM Numbers: John Deere GC00175, GC00344. Size: 21" Length, 2 3/4" Width, 3/8" Center hole, 0.119" Thickness, 1/2 Outer Hole. Manufactured to meet or exceed OEM specifications. Proudly made in the USA.