3 total CBL - Texas Instrument pH Amplifier Probe for CBL

Description

I have 3,
for the price of 1
- - Probe has been used in a lab and classroom setting and are working.  I am selling these for inexpensive since the manufactures says they lose accuracy after three years, so I am selling and buying new ones to be as accurate as I can get.  Otherwise, for a classroom setting thesis are fine.