This stool does what it says it does. Main reason for this review is to give an update on earlier comments, made by other reviewers. As the listing mentions, there is a new seat design. So what I received looked like the third image in the listing, with a mushroom-shaped rounded seat, rather than the flat seat shown in the first two images (April 2019). The (new?) fabric seat cover has a very good grip, so no hint of slippery. It is also well cushioned, so I had no problem using this immediately, for several hours. I was surprised to realise that I did actually use it at a very steep an angle for most of the time, as pretty much shown in the third image (woman on the desk) - I hadn't expected this. For me, this stool works well both sitting at a normal desk and on a standing desk. I'm 182cm / 6ft tall. I could imagine that for someone with shorter legs than myself, this stool could be somewhat too tall for really long periods on a normal desk, even at it's minimum height. I can comfortably sit on this, also as if it was a 'normal' stool, so with the stool totally upright, which allows me to use it continuously, even when I tire from using it leaning, as intended. I am not sure if this would be possible / comfortable with shorter legs, but maybe that's a small point. Because this is mentioned in another review, I should also say that I'm a guy and unlike suggested elsewhere, the shape of the seat doesn't cause any discomfort - I assume that's down to the new seat cushion shape? The stool arrived in time and comes in four easy-to-assemble parts. Regarding the health or 'well-being' effects of using this: I'm no expert in this area, and I didn't suffer any major back pain, just tiredness and stiffness after long periods of sitting without moving. So I can only talk from my own first immediate experience. I do notice a real difference using this stool, compared to a normal desk chair. I feel less tired or tense, and more active after long periods of sitting - so that's of course a good thing, and what I had hoped for! I rate this four stars, rather than five, for two reasons: - please remove the old pictures from the listing, as otherwise you don't really know what you get until it arrives! - the price is slightly steep I think. It is a well-made and thought-through product, and I have no problems using it for extended periods. It also seems to be the genuine product, rather than a cheap copy of someone else's design - although I'm no expert on this! At £138, it's an ok price but not exactly a bargain though. Review refers to the blue option.