Oh, c'mon Rick,
devils advocate here:

You mean you can get the same thing accomplished, with just a cassette tape? (I use an old VHS tape, kinda like the 8 track )

You're saying, you don't have to spent 20+ dollars, drill standing rigged parts of boats, and use a simple tape somewhere that basically does the same thing? c'mon now!

Actually a rarely use the tape either, just feel in the hairs of my forearms, and the tell-tales on the sails, my spin has tell tales too. Drives my crew crazy sometimes. I'll probably start using the tape more though, sometimes, the old hair on the forearam technique isn't quite as accurate on the true wind 8*)