Here are some common functional sock concepts:

1. Compression socks: Compression socks have a tight-fitting design that can provide moderate pressure, promote blood circulation, and reduce leg fatigue and swelling.

2. Antibacterial socks: Antibacterial socks use special antibacterial materials to inhibit the growth of bacteria and reduce odor and the risk of infection.

3. Moisture-wicking socks: Moisture-wicking socks are made of moisture-wicking material that can quickly absorb sweat and drain it away, keeping your feet dry and comfortable.

4. Thermal socks: Thermal socks use thermal materials, such as wool or thermal fibers, to provide extra insulation and prevent feet from freezing.

5. Sports socks: Sports socks use special designs and materials to provide extra support and cushioning, reduce friction and pressure during exercise, and improve comfort and performance.

6. Orthopedic socks: Orthopedic socks use special design and pressure distribution to help improve foot problems such as flat feet, collapsed arches, etc., providing additional support and stability.

In short, functional socks provide additional protection, comfort and support through special designs and materials to meet people’s specific needs in different scenarios.