I'm selling this because I'm decluttering, even though I've been using it. It's a Gymnic ball, so it's made more durably than commercially available balance balls, and it's stable, so I recommend it. If you were interested, how about it? I'm selling the air pump and the balance ball cover separately purchased as a set. (The cover has some stains, etc., because I've been using it with the cover on) - Balance ball with a maximum diameter of 55cm - Air pump - Balance ball case, gray - Brand: GYMNIC - Model name: CLASSIC - Size: Maximum diameter 55 cm - Accessories: Air pump - Instruction manual: Soft Gymnic instruction manual Please ask any questions in the comments section.