MANTRA SPORTS Yoga Exercise Ball Chair for Office Desk with Base, Ideal for Pregnancy, Birthing, Stability Exercises & Fitness. Swiss Stability Birth Ball for Labor, Gym & Workouts.

This type of chair/ball was recommended by a friend, who also has one. I purchased it because I am working from home, sitting for long periods of time. I am a teacher, so I need something stable (so I don't slide around in front of the camera--lol) but also something comfortable. I have 3 desk chairs at my house, but I wasn't happy sitting in any of them for long periods of time. As a teacher, I am used to walking around for most of the day, and I prefer that to sitting.This ball is perfect. I like that I can inflate it to the desired level of firmness. I followed the directions and inflated it in installments. So far, for the first few weeks, I notice that I need to add air every few days. This is not a problem. The chair comes with this little plastic tool that makes it easy to take the plug out, and the pump that came with it is super easy to use.Stability is good. It generally sits inside the inflatable ring it came with. I do like to kind of roll back and forth between classes or between grading, so I'm sure if I were just sitting still it would be a little more stable. In rolling back and forth, I am able to roll out of the inflatable ring, though I suppose I am doing that on purpose.Sitting on the exercise ball helps my posture. I am not slouching or anything like that. I did purchase the largest size so I could be at the correct level at my desk (even though the largest size was not recommended for my height if this were only to be used for exercise. It is a bit bigger than the regular exercise ball I have for working out). The only time something hurt was when my elbows (of all things) hurt. I realized I needed to add more air to the ball so I would be seated higher in relation to the keyboard. Then all was fine.I do feel stronger after sitting on this all day. I'm pretty sure it is engaging my core muscles in a way that a regular chair would not. And, as a teacher, that helps me to feel more alert, the way I would when walking around the classroom.The arm bands are a bonus, and they are the reason I purchased this as opposed to others. During meetings when I can turn off my screen, it is a good way to get a bit of blood flowing through the body and not feel so lethargic and sluggish. So far it has held up well to several weeks of use. I imagine when I return to the classroom I would consider bringing this with me.

Update: The first ball randomly developed a small tear in it after 2 months. I contacted Mantra, and they gave me no trouble replacing the ball, were prompt in responses, and communicated clearly with me.The new ball is much more spherical, not the lopsided shape the first one was. It's doing great so far. I expect it to do better because it doesn't have the obvious issues the first one did. I suspect this is more representative of the product.I'm still using my original stabilizing ring, though it has some bulges. I tried to reduce the air pressure inside it because I didn't want to risk a rupture in it too, but that made it too soft and less effective. I reinflated it back to be much stiffer, and it works much better. Still no problems from it. I suspect it may be from the same batch of rubber that was just a bit off, but it's holding up so far, and I have a backup from the replacement they provided me.They had me re-order the same kit from Amazon for my replacement, instead of any direct shipping. But they were true to their word and immediately refunded me. I think I actually got my refund before the new kit, and the new kit arrived in 1 or 2 days.I'll update if things go sideways within a year. If I don't, everything has gone well and I can definitely recommend the product and the company.Original review:Overall I like the ball. The donut (ring base) is a great stabilizer and is also holding air well. It seems very stable, I have no worries at all about bursting the ball, and the straps and "adjustable" resistance bands are a nice bonus.But my ball is more of a lopsided egg than a sphere. This is very obvious looking at it and setting in on the ground. Using their adjusted tape to measure the ball's circumference, it's almost an inch shy of 75 inches on one side (air hole to air hole), and more than an inch over around the circumference where the seam is, perpendicular to the smaller circumference. That leaves a question, which way am I supposed to measure the ball for inflation?Also the adjustable resistance bands are a bit flimsy. They're made of soft plastic and the first few times I adjusted them they slipped right out. The last time I turned them what felt much too tight and felt like it would strip the screw, if not the threads on the handle, but at least it held better. The resistance isn't very high, the estimate of 10-20 pounds seems accurate. But adjusting the travel before the resistance picks up is nice.Overall I'm pleased with the ball, and I think the base is a very strong, if not almost necessary, addition to the ball. The resistance bands and canvas rings to tie them to the base are a nice bonus, but I don't expect them to last and the velcrow rings for ankles from a $25 set of resistance bands are much better (but not adjustable in length).I'd still easily buy the ball again, and only hesitate on giving it 5 stars because of it's ovoid shape.

The ball itself has been serving me well, as I've been using it regularly since it arrived. It does what it is supposed to do and is holding up nicely.Unfortunately, the accessories that came with it left much to be desired. The pump included in the package doesn't really do a good job — it might even be better without it.Moreover, the balance tube that was part of the package arrived punctured, which I noticed only after discarding the packaging. While this issue didn't stop me from using the ball, it did prevent me from taking full advantage of all the functionalities supposed to be offered with this purchase. I reached out to the seller to provide feedback on this matter, but there hasn't been any response or attempt to address the issue, which was a letdown.While I appreciate the quality of the ball, the lack of response from the seller and the condition of the other components have influenced my rating. It has made me reconsider purchasing from them in the future. Please