Compatible with the following OHAUS Electrodes: pH Electrode ST210 (Cat#41-2000) ; pH Electrode ST230 (Cat#41-2001) ; pH Electrode ST310 (Cat#41-2002) ; pH Electrode ST320 (Cat#41-2004) ; pH Electrode STPURE (Cat#41-2010) ; pH Electrode, ST260, EN (Cat#41-2003) ; pH Electrode, ST350, EN (Cat#41-2005) ; pH Electrode, STSURF, EN (Cat#41-2011) ; ORP electrode STORP1(Cat#41-2012) ; ORP electrode STORP2 (Cat#41-2013) ;