For a power cable for a desktop computer that's 1.8 meters long and 8mm in diameter, here are some key points to consider:

1. **Type of Cable**: Ensure it’s a standard C13 power cable (also known as a kettle lead) commonly used for desktop PCs.

2. **Connector Compatibility**: Check that one end fits your power supply unit and the other end fits your wall outlet.

3. **Voltage Rating**: Verify that it meets the voltage requirements for your region (typically 220-240V for many countries).

4. **Quality and Certification**: Look for cables with safety certifications (like UL or CE) to ensure they meet safety standards.

You can find these cables at electronics retailers, online stores, or computer accessory shops. If you have specific needs or preferences, let me know!