Item does a good job for the most part, it does get thrown off a lap or two when you stop or glide too much, but not that much, I swim for 2.5 mile sessions at a time 2 to 3 times a week so I used to loose track all the time before it. The instructions tell you not to hit the buttons when your in the water. So I start and finish it standing up. I got it for Christmas last year, and I wouldn’t know how to swim without one anymore.
If you are going to lap swim its really the most effective tool. All the other versions were too cumbersome. Trying to remember to hit the lap counter on the Timex was just complicated since I breast stroke.
Pretty effective!