Mulching Blade / Exmark 109-5876-SPack Size:1Exmark 109-5876, Exmark 103-9610, Exmark 109-5876-SJ. Thomas BO-506, NHC 212-0181, Rotary 11775Exmark Lazer Z HP (600,000 and higher); Requires 3 for 50" deckLength: 17 1/2 ", Center Hole: 15/16 ", Width: 3 ", Thickness: .209 "