DeskripsiA 500mL bottle of 200mV ORP Calibration Solution. Purchase and use this standard solution to calibrate your Pyxis Lab® ORP inline or handheld devices, including:ST-711 Inline ORP SensorST-712 Inline pH ORP SensorpH/ORP Module Attachment & HandheldThis calibration standard can calibrate any water treatment device that measures for ORP but is specifically meant for Pyxis Lab® devices.