• Displays ORP (pH/ORP – #638-850-04) and temperature.
• Floating, waterproof casing.
• Replaceable pH and ORP cartridges.
• Cloth pH junction is easy to clean in case clogging occurs.
• Automatic shut-off after 8 minutes of non-use.
• Automatic temperature compensation for #638-850-04.
• Automatic 1 or 2-point pH calibration (#638-850-04 only).
• Battery % level at startup and stability indicator.
• Supplied with four 1.5 V batteries.
• Dimensions: 16.3 x 4 x 2.6 cm.

Specifications:
ORP Range: ±1000 mV
Accuracy: ±2 mV
pH Range (#638-850-04 only): -2.00 to 16.00 pH
Accuracy: ±0.05 pH
Temperature Range: -5.0 to 60.0°C, 23.0 to 140.0°F
Accuracy: ±0.5°C/±1°F