I love this product, is very durable and does exactly what i want if not more (i have abused it). The 75cm I must admit looks huge when i do exercises in my living room (and I am also tall 5'11''). However, this was the size I was used to exercise at my bootcamp and the space there was more open, which didnt make the ball seem as large as i see it in my living room. It is definitely for taller people (when you sit on it your legs shouldnt be on the air!!!) but you can find the right dimensions online. What i also love is that it came with a big poster-size almost exercise chart (which is very helpful) and it even explains the dimensions you should buy depending on your height. Love it!