I received this mini ball as a gift, and I have been using it for fitness, mainly with the workout Tracey Mallett-Pilates Super Sculpt. I also purchased a similar ball, 9" Body Back Ball & Pump, so I will be comparing the two balls in this review.The Overball that I have looks just like the blue one pictured above. As you can see, the surface of the ball is covered with slightly raised dots; this improves the ball's gripping surface, making it easy for the Overball to stay in place under your back, behind your knee, etc. The Overball comes with a small, short plastic straw to inflate it and a small plastic pin to use once the ball is inflated. The ball fills up easily enough with the straw; I found that the inflation process took only a minute or so. The problem I had was when I went to insert the pin. The Overball does not retain air very well at all, so every time I tried to insert the pin, the ball deflated almost completely in the brief moments it took me to get the pin in place. I had to repeat the process several times; finally, I inflated the Overball way beyond the point where I wanted it to be, put the pin in as quickly as I could, and was satisfied with the results. I did not have this same problem when inflating my Body Back Ball (which comes with its own nice little hand pump); that ball definitely seemed to hold the air better to allow for pin placement.In terms of actual performance, I have had no problems with the Overball. It does seem a little squishier than my Body Back Ball, but that might be because of the inflation issues--if you are looking for a firm ball, this is definitely NOT the right choice! But for use with Pilates and other core workouts, where a slightly deflated ball is desirable, the Overball works quite well, and I would recommend it overall.