I have 10 bolt duals and 12 bolt spacers that I used on my John Deere 4830 sprayer. The spacers are 12 bolt on one side and 10 bolt on the other. They are Firestone 320/90 r50. One is at 10% and the other is at 30%. They do really good with helping float. Asking $1700 obo. Call or text 618-420-4420.