78267 New Western Fisher Blizzard 3/8 Well Nut Set (2 pack)

A New Western 3/8 Well Nut (pkg of 2.) Tornado Poly Caster Ice Chaser Poly Spreader 1.5, 1.8, 2.5 

Part # 78267 gives you 2 grommets. They also sell it with the bolts as part # 78268.

This is for a poly Western Tornado hopper spreader model. 

This also fits on the Fisher Poly Caster and Blizzard Ice Chaser

For related parts and diagrams, check this document.