903 Ballhead..................Small-2 1/2" x 1" diameter. Perfect for compact cameras, SLR's, and smaller video cameras. 

904 Ballhead..................Medium  3" x 1 1/2" diameter. Can accommodate larger SLR's and mid size video cameras.

905 Ballhead..................Large 3  1/2" x 2" diameter. Ideal for long lens photography  and Medium Format work.