73350800 Jam Nut and 73800800 Lock Nut, Typically Used With The 175698 Trunnion (not included) 2 nuts, one 73350800 Jam Nut and one 73800800 Lock Nut Used on each side of the 175689 Trunnion (not included) Typically found on the 173288 or 127218 Link Arm used on 42" decks. (not included)