AYP 121798X, Husqvarna 532121798, Craftsman 121798X, Viking 6109-004-1006, Poulan 532121798AYP Requires 3 for 50" deck; Husqvarna Requires 3 for 50" deck; Viking Requires 3 for 50" deckLength: 17 5/16 ", Center Hole: 3/8 ", Width: 2 1/4 ", Packaging Type: Branded label, Thickness: .187 "