> For the complete documentation index, see [llms.txt](https://docs.rapt.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.rapt.io/equipment/rapt-laser-level-sensor/assembly.md).

# Assembly

### Assembly

**The RAPT Laser Level Sensor - Cornelius Keg Lid Kit is pre-assembled**

Before use inside a suitable Cornelius keg (such as a [KegLand 19L](https://kegland.com.au/products/19l-new-ball-lock-keg-free-beverage-tag-low2-o-ring) or [9.5L Ball Lock Keg](https://kegland.com.au/products/9-5l-ball-lock-keg-premium-brand-new)) please clean the underneath of the pre-assembled lid and housing, and ensure the keg lid and keg are both clean and sanitised before use.

The **RAPT Laser Level Sensor - Cornelius Keg Lid Kit** is rated to **IP68**.

Before use, the batteries must be installed in the battery holder. The battery holder must then be correctly installed in the RAPT Laser Level Sensor.

### Installing Batteries

{% stepper %}
{% step %}

### Remove Top Housing

Carefully unscrew the top housing from the RAPT Laser Level Sensor. Remove the battery housing and board assembly as shown.

<figure><img src="/files/GKUzdFUg5XywysCz9hXA" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### Remove the Battery Housing

Carefully pull out the battery housing. Install 3 x AAA Batteries, ensuring correct polarity. The Negative terminal is indicated by springs in the battery housing as shown

<figure><img src="/files/6BR88LHD8yao51wwG6xE" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### Install the Battery Housing

Once the batteries have been installed in the battery housing, replace the housing in the Board Assembly. Note: The battery housing is directional. Follow arrows as indicated on housing. Line up the battery housing with the board housing as shown

<figure><img src="/files/xcp9gEYnel6cnkqPu2Jh" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### Install the Board Housing into the RAPT Laser Level Sensor

Carefully replace the Board Housing into the RAPT Laser Level Sensor housing. Screw the top housing back onto the RAPT Laser Level Sensor housing, ensuring that it is snug as pictured.

<figure><img src="/files/gD56nJ0mRSqH0n37VqYX" alt=""><figcaption></figcaption></figure>
{% endstep %}
{% endstepper %}

Once the battery housing is installed the RAPT Laser Level Sensor will automatically enter Bluetooth Pairing mode for approximately 5 minutes, allowing it to be registered to the RAPT Brew App. Bluetooth Pairing Mode is indicated by the LED blinking Blue

If the RAPT Laser Level Sensor does not enter Bluetooth Pairing mode then this can be entered manually - refer [**Operation**](/equipment/rapt-laser-level-sensor/operation.md)

To Register the RAPT Laser Level Sensor to the RAPT Brew App refer to [**Registration**](/equipment/rapt-laser-level-sensor/registration.md)