Ag/AgCl reference electrode is a kind of commonly used reference electrodes.
AgCl + e = Ag + Cl- E0 = 0.199V vs. NHE 25 C
D.J.Ives and G.J.Janz, "Reference Electrodes," Academic Press, New York, 1961
The electrode is composed of Ag/AgCl/Saturated KCl solution. It can be inserted into solution directly for general measurement.
For avoiding Cl- ion or nonaqueous solution measurement, it betters to use holder. First, add the solvent and supporting electrolyte into holder, and then set the electrode into the holder. Last, insert the whole electrode into test solution.
It is easy to refill or change the saturated solution of KCl. The electrode is long-lasting.

The electrode is made of glass. The electrode liquid junction is made of Porous ceramics .

Electrode length: 105mm (approximate)
Length from joint to bottom: 60mm (approximate)
Diameter from joint to bottom: 5mm (approximate)

Length of holder: 85mm (approximate)
Diameter of holder: 9.7mm (approximate)

Price $98 or EUR98