These balls are NOT dimpled out on the sides. They are solid round rubber balls (Ethylene Propylene) made for ball & socket rings (where the ring comes and clasps around the ball). These are great for being able to take balls in/out easily since they are made from rubber and are somewhat flexible.
1/4" ~ 6mm5/16" ~ 8mm3/8" ~ 10mm1/2" ~ 12.5mm5/8" ~ 16mm