Seattlers! Microsizers/Tomy Lap Counters
 

I hope tis not considered spam. Also since there doesn't seem to be a main forum, I will post in the two most relevant places.

The local Goodwill near Beacon Hill in Seattle has about 13 of the Lap counters.. NEW (though some have been opened by people not knowing what they are). For $3.00.

Steal! Got one for me and my cousin for our ZZSE's. :)

And no, Im not trying to buy for others.. after shipping and stuff, you can get a RS version for about the same, but if you live in this area, its a great deal. They have them over on a shelf near the book area.. not with the toys (Dont think they realized what they were).

Is this the lap counter that you're refering to?

I have seen that lap counter before, and always wondered specifically how it worked. The RS lap counter has a main unit as well as a "reflector" unit. The main unit has two IR sensors in it, and the reflector unit has two IR LEDs in it. The lap counter measures the time that it takes from when the IR light beam is broken between one set of the IR LEDs to the second set (hence measuring FPM).

Judging by the pics and the battery requirements of the lap counter in the link above, it appears that counter only has one unit, which is why I always wondered exactly how it worked.

Well this site broke your link, but most likely its the one your thinking off. It does seem to have two sensors, but Im not sure on of them is IR. There is a smaller hole next to the large IR, buts its too deep to see what it contains.

So I'm thinking that there is indeed only one unit (not two like RS's)? BTW (I figure that it does), does it measure FPM? What do you think of that one verses the RS lap counter?