# B01 Vol.Unit
### Definition
Sets the flowmeter’s instantaneous flow volume unit. Default: L (liter).
### Notes
N/A
### Operation Procedure
Button Functions(Click to Expand)
When the main screen is displayed in **green backlight**, the four buttons function as follows:
* **Blue Button (leftmost):** Return, exit, or save settings.
* Gray Direction Buttons:
* **Left Gray:** Previous Page, decrease value, or select item
* **Right Gray:** Next Page, increase value, or select item
* **Orange Button (rightmost):** Rightmost button: Enter settings, edit, or confirm selection
{% hint style="danger" %}
**Do not hold buttons for extended periods to avoid damage.**
{% endhint %}
{% hint style="info" %}
Button functions may change depending on the operation context to improve usability or prevent accidental presses.
{% endhint %}
```
B01 Vol. Unit Setting Steps
• From the main screen (green backlight),
press Orange Button (Setup) to enter settings (orange backlight).
• Use Gray Arrow Buttons to select B.Unit , press Orange Button (Enter).
• Use Gray Arrow Buttons to select B01 Vol. Unit, press Orange Button (Enter).
• Use Gray Arrow Buttons to choose the options.
• Press Orange Button (Set) to confirm.
• Press Blue Button (ESC) to return to the main screen (green backlight).
```
| Options | Description | RS-485 Numbers |
| ----------- | ----------- | -------------- |
| L (Default) | Default | 0 |
| m³ | | 1 |
| US gal | US Gallon | 2 |
| Imp gal | UK Gallon | 3 |
| *ft*³ | | 4 |
> Refer to the [Read/Write Memory List](https://docs.lorric.com/qr/fu-es-echosense-instruction-manual/communication/modbus-rtu-protocol/read-write-memory-ram/read-write-memory-read-list) for the Modbus command format. This parameter uses the Int16 data format.
**Orange Button (rightmost):** Rightmost button: Enter settings, edit, or confirm selection
{% hint style="danger" %}
**Do not hold buttons for extended periods to avoid damage.**
{% endhint %}
{% hint style="info" %}
Button functions may change depending on the operation context to improve usability or prevent accidental presses.
{% endhint %}
