DIFFERENCE: minimum desk height of 26" is required for the size. Measure your desk before purchasing It is the Original Active Sitting Ball Chair Solution for use at the office, home in the living room, classroom, or the gym. Suburb complimentary ergonomic alternative sitting stool solution for desk sitting and standing desk^ Health: Activates back and core support muscles which promotes good posture and can potentially relieve back pain for Adults and children. Comfortable substitute for pregnancy birthing ball, labor ball, or Medicine ball^ Perfect for ab engagement, yoga, back stretching, posture workouts, therapy, and physioball balance training routines, also promotes flexible joints for healthy lifestyle.^ Patented Self-Standing base design with a weight limit of 400lbs and extra thick carry handle makes the seating the perfect combination of a swiss fitball and ergonomic office chair. And two matiral are avaiable: rough felt and super fiber cloth.^ Packed: There is a yoga ball with one more air plug , a ball cover,a pump for inflation and also a instruction. Some effort needed for set-up, use included accessories (hand pump /air pump adapter) to inflate inner sitting ball until outer cover is completely filled. Please contact us if inner ball appears to be too small or pumping takes longer than 20 minutes.