Ball size is dependent on the size of the trailer coupler. The trailer coupler size depends on the gross trailer weight (GTW in the chart below). The trailer's coupler size should be stamped on it.
Richard & Jill
2014 Flagstaff 832IKBS Classic Super Lite
2018 Silverado 1500 Crew Cab Z71 4WD All Star Edition
Camping since 1989
Car Shredder Op/Tech, Scrap Metal Recycling - retired
Everyone gets confused at some time, some are better at hiding it than others.