Uniform 10" diameter allows for consistent performance for all users and fitness levels. Soft and grippy cover won't slip during the most vigorous partner exercises - making for safer throwing and catching. Long-lasting seams reinforced with threads that won't stretch or wear out. No bounce construction for added safety. Sets include UltraFit™ Evolution™ Kompact balls, all-steel UltraFit™ rack, and a set of 3 laminated UltraFit™ Charts.