The pocket type pH meter is a waterproof ph tester for water with a 0.1 pH resolution and an accuracy of ±0.1 pH. It has many advanced features that are found in more expensive portable instrumentation. One or two-point calibration is automatic to two selectable buffer sets (4.01, 7.01 and 10.01 or 4.01, 6.86, and 9.18). The pHep®4 also features a replaceable electrode with a stainless steel round connector. This cartridge design has no pins to line up or that can break. The HI73127 replacement pH electrode also features an extractable cloth junction. The extractable cloth junction of the HI73127 allows for the renewing of the junction. Simply extract ⅛” of the junction by pulling on the junction will expose a new portion. Any clogging that was present will be cleared and the response time will be back to normal extending the life of the pH electrode.