Ball Diameter	Person's Height
30 cm - 11.8"	Under 4' 6"
45 cm - 17.7"	4' 6" to 5' 0"
55 cm - 21.6"	5' 1" to 5' 7"
65 cm - 25.5"	5' 8" to 6' 1"
75 cm - 29.5"	6' 2" to 6' 7"
85 cm - 33.5"	6' 7" and up
All balls shipped deflated.