What are the common head types of four cut screw bolts?

Common head types of four cut screw bolts include:
1. Hexagonal head:
The common head type, suitable for tightening with various tools (such as wrenches), providing large torque, suitable for industrial and architectural installations.
2. Flange head:
Flange head bolts have a head with a rounded or rectangular edge, which increases the contact area and helps to evenly distribute pressure. It is suitable for applications with large loads.
3. Countersunk head:
The head of the countersunk head bolt is designed to be conical, which can be completely sunk into the surface of the material, suitable for applications that require a flat surface.
4. Flat head:
The top of the flat head bolt is flat, often used for installations that require a smooth surface, and can be flush with the surface of the material.
5. C-type head:
The head of the C-type head bolt is semicircular or C-shaped, and is often used in special design fixing applications.
6. O-type head:
O-type head bolts are usually used in decorative applications, and the head is rounded for smooth installation.
7. Pan head:
The head of the pan head bolt is disc-shaped, suitable for installations that require a large contact area, and is often used for fixing wood and other soft materials.