First thing's first, these are pretty good goggles, the tracker does work, and it's helpful when swimming laps, sets, generally normal swim practice. The thing ships in nice boxes, a separate one for the tracker and goggle, and it's highly giftable if you have a swimmer you're trying to gift this to. It looks great coming out of the box and is a bit of an event. I didn't really appreciate that I have to install the tracker in the goggle, but I think the point is that the tracker can be reinstalled in a new pair of goggles. The goggles are equivalent to a nicer TYR, Speedo, or Nike pair, with silicone straps that don't pull the hair (and were pretty narrow but comfortable) and changable nose pieces instead of the kind that can push in to your nose. You get several nose pieces that just slide out of place. I found the ones already in the goggles worked perfectly, but they were easy to swap. The straps were fine for holding a little mp3 player, and had plenty of slack. The tracking device clips into the goggles with two loud clicks, so there's no doubt it's in place. It doesn't move at all, and you can charge it without removing it, and in fact I don't plan to ever remove it unless the goggles fail (even then, I'd just change the strap or nose piece). There's a fairly thick, kinda greasy anti-fog applied, more than I'm used to, in the goggles, and when I installed the tracker I got a huge thumbprint on the anti-fog I had to try to smooth out. As most swimmers know, you try not to touch the inside of new goggles for this very reason, and I was very annoyed that my expensive goggles were smudged, almost by design, for no reason. All that aside, it was fun to swim with these. Setup in the app was easy, but the app takes a long time to start each time. Once you're setup you need to tell it where the pool is (no good reason for this except to sell the data) and the length of the pool. I have a pretty bad astigmatism and the readout is very easy for me to read. You have to deliberately look to the left to see the number (the position of which is adjustable in the app). You lose a little of your view to the left, but it's actually not a distraction when you swim because it's way over to the left, but it's still very easy to see whenever you want. While swimming, I noticed the tracker corrects itself. If it thinks you did a flip turn, but you are resting, it fixes it. If it thinks you're resting but you continued your set a little slowly, it corrects it. It does make mistakes, but rarely. So long as you're finishing your length of the pool, it will know your distance. I appreciate that it tells me how long I've been swimming, the actual time of day, and when resting how long I've been resting. It's gentle encouragement to keep swimming. You also obviously get how many laps you have swam (lengths of the pool, not laps, are reported). I can swim a 500 or a mile without debating how many laps I've done when I'm at 16 or 20, which is particularly great as I listen to music when I swim. It's a total game changer for me. When you are done swimming, you hit the single button on the outside of the goggle and an amber light blinks for a few minutes, when the tracker is trying to pair with your phone. All you have to do is open the app, and it should transfer the swim data. The phone app takes so long to open this can be annoying, holding your phone right out of the pools, dripping everywhere, so I try to open the app before I swim. I've had mixed results getting the goggles to actually transfer data, but for me, just knowing how long and far I swam during my workout is good enough. The app clearly needs some work. This is only a three star product because it is obviously very overpriced for a waterproof accelerometer and nice goggles. I like it, and I use it, but the value isn't there. I hope when the company takes off they lower the price quite a lot, because the size and limited scope of what this does is perfect for a lot of swimmers, and it's an easy to use device.