# ``ctd_redox_potential_raw``
## Properties
:dimensions: N_PROF, N_LEVELS
:dtype: float64
## Default Attributes
| Attribute | Value |
|-----|-----|
|``whp_name`` | ``CTDORP`` |
|``whp_unit`` | ``VOLTS`` |
|``units`` | ``volts`` |
|``C_format`` | ``%9.4f`` |
|``C_format_source`` | ``database`` |
## Description
Oxidation-reduction (or redox) potential sensor. Measures the tendency of various chemical species to gain or lose electrons. In the ocean, it is useful for detecting hydrothermal plumes. Usually the absolute value of ORP measured by one of these is not useful but the change in potential over the profile is.
:::{warning}
The actual scientific units for this parameter is a voltage, usually reported in millivolts. We use VOLTS for the raw sensor output, typically 0V to 5V, and millivolts for scientific units which can be negative.
:::