Seems pretty pointless. It's pretty easy to use a pace clock to help count. You can see it from the water without stopping and it helps you keep on pace.

I have heard of some people using it and they have all seemed to like it ok. I just use the lap function on my wrist watch to keep track of laps.

I use one of the following:

http://www.sportcount.com/products.php

I thought it was simpler than using a sports watch - since you just use the thumb on the same hand to hit the lap button.

I also use the sportcount. Not coming from a swimming background, I have no idea how to use a pace clock. In addition to counting laps, Sportcount gives you the fastest, slowest & average lap times, which I think is cool.

I've been using the sportcount - it's nice because you don't have to set it up on a wall. It's just there on your fingertip. It works great for me.

I've tried using the lane line as an abacus, but as the laps increase it gets a bit ridiculous and going by every 100 yards I start losing track again. I like the sound of that sportcount.

I got the Fins lap count as a hand me down. It works ok, but the price tag of $75 isn't worth it. If you just need something to count laps, the sport count that RV gave the link for may be the better way to go.