Opto 22 SNAP-pH/ORP Differential Voltage Measurement Input Module, 2 Channel Input, 5 VDC (+/- 0.15) at 170 mA, -1.00 V to +1.00 V for ORP Probes Input Range $325.00 B0058V0TSO
Opto 22 G4ODC5R5 G4 Reed Relay Output, Normally Closed, 5 VDC Logic, 1500 VDC I/O Isolation, 14mA Logic Input Current $22.00 B00597VDTQ
Opto 22 G4PB4 G4 Digital 4 Channel Mounting Rack $38.98 B00597WOGC