  Platinum electrode. 
This glass loop contains two platinum electrodes a fixed distance apart.  Dipped into a liquid it can be used to measure the conductivity of the liquid, thus indirectly measuring the concentration of something, salt for example, in the solution.  Platinum is a good material for such electrodes because it does not corrode even under very strong chemical attack. 
Source: eBay seller gainexpress 
Contributor: Theodore Gray 
Acquired: 17 April, 2009 
Text Updated: 17 April, 2009 
Price: $25 
Size: 0.25" 
Purity: 99%
 |  
  |  
 |  
  |