HI7041L is designed to refill the electrolyte solution for polarographic dissolved oxygen probes. Polarographic sensor technology is based on the Ross and Clark polarographic measurement method. An oxygen probe is composed of a platinum electrode and a solid silver electrode. The HI7041L is a concentrated Potassium Chloride solution held in place over the electrode by a PTFE (Polytetrafluoroethylene) membrane. With polarographic technology, an external voltage is applied to the platinum cathode, silver anode, electrolyte solution and gas-permeable membrane to establish a current that is proportional to the concentration of oxygen in a solution.