The specific screws needed for a solar panel installation can vary depending on several factors, including the type of mounting system being used, the material of the roof, and other local conditions. However, there are some common types of screws and fasteners that are often used in solar panel installations:

1. **Lag Screws**: These are large, heavy-duty screws that are commonly used to attach mounting rails to the roof structure. They provide strong support and are designed to withstand the weight of the solar panels.
2. **Self-Tapping Screws**: These screws have a sharp tip that can cut its own threads into the material as it is driven in. They are often used to attach mounting brackets or other components to the roof.
3. **Hex Head Screws**: These screws have a hexagonal head that can be tightened using a wrench or socket. They are commonly used in solar panel installations due to their durability and ease of installation.
4. **Wood Screws**: If you are installing solar panels on a wooden structure, you may need wood screws to secure the mounting system to the roof.
5. **Roofing Screws**: If you are installing solar panels on a metal roof, you may need specialized roofing screws designed to work with metal roofing materials.