Vernier Probes

A couple of people have asked me about the Vernier probes.  I was first introduced to these probes in 2002 when I participated in an NSF Chautauqua program in conjunction with UT Brownsville.  We took probes to El Cielo, Mexico to conduct water quality samples in the Rio Sabine.  These were the variety that attach to the TI scientific calculator.  I don't recall the model numbers.  I know that you can also purchase probes that plug directly into the USB port on a computer.  I have not used these myself.  I attended a workshop at the K-20 center in Norman last fall.  They delivered lab curricula to us to accompany a new Labquest Pro with a temperature probe to start off with.  I believe the probes themselves are interchangeable.