Unique Glass Membrane - The PHE-17 pH electrode uses a micro cylindrical glass membrane (4mm in diameter), making micro-sample pH testing easier than ever, and can be tested in high-temperature samples (up to 212°F). The stainless steel protective cover ensures the durability of the slim glass tube. Long-Life Reference System - composed of a glass, AgCl, and a reference silver wire. The top end of the slim glass tube is stuffed with cotton, which prevents the reaction between AgCl and electrolyte when the temperature changes. It improves the stability of reference electrode and extends the service life of the electrode. The electrode uses a BNC connector, compatible with any labForce® pH meters.