Gone are the days of mystery movements of exercise balls everywhere. Keep your exercise ball in one place with Incline Fit exercise ball base. Made from a hard but lightweight plastic, this durable exercise ball base also provides increased stability for those just beginning to work out with an exercise ball. By keeping the ball in one place, people starting to exercise can stay put while building muscle and improving flexibility. Similarly, seasoned exercisers can execute more difficult workouts more accurately while the exercise ball stays in one place. The small openings on the sides of the base can also assist exercises incorporating resistance bands. Works well with65 Cmand75 exercise balls.