The inner part is the entire optic from plug to the led tube.
It's very easy to replace the inner part of the lamp when you follow these instructions:
- Place the lamp upside down
- Unscrew the screws
- Lift the electrical part
- Replace the electrical part
- Don't forget to place back the rubber ring into the lamp. This keeps the lamp waterproof.
- Put the screws back
- You can now use the lamp