Coollang Tennis Swing Analyzer

I was pretty skeptical about a product like this. How in the world could a tiny round stick on device going to keep track of all the awesomeness of my tennis game... well, I learned 2 things... 1. It does a really good job doing it and 2. I'm not really that awesome!I used the double sided stick-um to adhere it to the bottom of my racket. Setup was really easy on my pixel 3. The app installed and it connected via Bluetooth first try.One thing to note, before you start each tennis round, you should connect to the device and sync it. If you don't, the first game will be added to the previous match stats. Other than that, it works great. I haven't counted my swings and had anyone measure my racket speed with a radar gun to verify the counts and speeds are 100% correct, but it's definitely in the ballpark.The things it keeps track of are: Total Swings per day, avg&max forehand swing speed, avg&max backhand swing speed, serve swing speed (remember, this isn't ball speed...it's swing speed). It also counts the types of swings you use during a match too... that I find very interesting.All in all a very cool device. I'm not sure if it will improve my game, but it will certainly let me know if/when my game is improving.**UPDATE: (2/18/20)... well, I had to take 1 star off. While it is still a good device to have, it keeps "self resetting" and when it does that, any stored info that hasn't been sync'd with your phone is lost. I normally sync just before a match and then right after a match... but if for some reason it resets during the match, all is lost. This has happened twice now, I'll 3 times a week, so twice in roughly 28 matches... anyhow, it's nice when it work, frustrating when you're having the game of your life and it loses it's data...

I don't recommend this product ,is difficult to add on the butt of the racquet. The sticker are useless and don't worked with some cell phone.

I bought this for my 13-year-old to study her tennis swing. It rarely worked. The sensor did not pick up her strokes despite trying it multiple times. It worked once and then didn’t work again. Not reliable enough.

The 1st smart tennis gadget I tried. Overall, this is a pretty good aid as part of match analysis and review. Although I have not tried the video analysis, but I don't think it is the gear if you are looking for more technical data like hitting spot, angle of contact, etc. However, it is my believe as an instructor that these gadgets along with video analysis can only reveal the symptoms, and, correcting a symptom takes a long of work considering a stroke starts from your feet and not the racket.The Coollang device's value is in its macro hitting stat which can reveal how well your game plan was executed. Which hitting style is more/less effective against an opponent. The device turns itself on pretty soon after a few hitting. The stroke type stat seems pretty close to how I recall the match went as I don't have a 2nd method to verify. The percentage of shots distribution reveals if you are able to play with dictation (more topspin/FH) or in plan B (more slice/BH). I wish there is a shot type distribution by time graph as this may reveal which hitting style is more effective at the time. The endurance/intensity is useful info maybe I will check it during the match to see if my mental focus is up or down.I think the device has a lot more potential with some software improvement. For example, if there is a set up to remember my preferred hitting positioning (like open stand FH, square-stand BH, etc.) and full stroke range, then the device should be able to tell in a match if I am able to get into position and hit more full-strokes or being rushed by an opponent, or if I am taking too big a cut on returns, etc. This could be valuable to work on specific hitting technique.Another feature I wish the software can do is to merge multiple devices' stat together. It is not uncommon for me to switch rackets in a match. The software should be able to get all the stats by time to give a complete picture.Pro: relatively cheap; easy to install (I used the 3M sticker); app relatively easy to use; useful stat for match analysisCon: can provide infoOverall, I think it is not a bad investment for $50 as most of 3.0-4.5 players probably don't pay much attention to play stat and simply chalking a