U-bolt, also known as a U-shaped bolt, is a non-standard part. It is called so because of its U-shape. Both ends have threads that can be paired with nuts. It is primarily used for securing tubular objects like water pipes or flat objects like car leaf springs. Due to its method of securing items, it is referred to as a rolled thread connection bolt.

Fully threaded and partially threaded are the two categories divided by thread length.

Threads are divided into coarse and fine types according to the pitch, with coarse pitch not indicated in bolt markings.

Bolts are categorized into eight performance grades: 3.6, 4.8, 5.6, 5.8, 8.8, 9.8, 10.9, and 12.9. Bolts with grades 8.8 and above (including 8.8) are made of low-carbon alloy steel or medium-carbon steel and heat treated (quenching + tempering), commonly referred to as high-strength bolts. Below grade 8.8 (excluding 8.8), they are generally known as standard bolts.