Milwaukee Instruments, SE300, Lab Grade Double Junction ORP Platinum ProbeThe SE300 probe is designed for use with the Milwaukee MW500 PRO ORP Meter. The Milwaukee Double Junction ORP Platinum Electrode probe makes ORP testing easy and low maintenance. The double junction design reduces risk of clogging.Using a gel removes the need to maintain the electrolyle levels. Combination electrode contains both the measuring half-cell and the reference half-cell to minimize electrostatic interference and provide consistent readings. The resin body is highly durable, chemically resistant and protects against accidental damage.