Bluelab PROBPH pH Probe for Water, Replacement Electrode for Meter, Monitor, and Controller with Easy Calibration, Tool for Hydroponic System and Indoor Plant Grow
Easy to clean because of its bullet shaped glass bulb. Fully waterproof and less fragile than all-glass electrodes because of its tough polypropylene barrel. Gel filled (non-refillable) making it maintenance free and a double junction reference providing longer life.