CS905 Non-aqueous Ag/Ag+ reference electrode is used in the organic system. It consists of a cap with a Ag wire, a glass tubing, and a porous glass tip sealed to the glass tubing with PTFE heat shrinkable tubing.
4mm/6mm refer to the diameter of the tube. In above picture, it's the size of 4mm non aqueous Ag/Ag+ reference electrode. 4mm is preferred by a lot of customers.
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