U-bolt, also known as u-card. A bolt commonly used in pipe installation to fix pipes. This bolt is shaped like a U-shape. Used to link two firmware. There are 4.8 grade, 8.8 grade, 10.9 grade and 12.9 grade. The hot-dip galvanized U-bolt is a U-bolt after hot-dip galvanized surface treatment, thus achieving anti-corrosion effect.