This may sound stupid, but I've had my stability ball for a couple of years, and never could get it really firm. I had a couple of different pumps, but it seemed like it was as inflated as it was going to get. When I got my Troy Lite, I also ordered the "Deluxe Ball Pump" for $10.50. It worked, and very easily I might add! My ball is fully inflated, my legs go at a 90 degree angle like they're supposed to, and boy, did it make a difference in my workout. I did both PUB and PLB this weekend, and I feel like it made a noticeable difference in both. I know this post probably sounds silly, but I guess I'm lazy when it comes to some things, and I just didn't push myself to try getting an attachment for my bicycle pump or basketball pump. Anyway, if any of the rest of you have been problems getting your ball fully inflated, you may want to try this pump. :7