Technical Specification U Bolts of standard size are essentially a single piece of mild or stainless steel bar that is threaded at the end of either side and then shaped as the letter U. U Bolt Dimensions range from M6 to M20 in terms of thread diameter, with various lengths and specials also available. Features A U-bolt is a bolt in the shape of the letter U with screw threads on both ends. ... U-bolt Material type (for example: bright zinc-plated mild steel) Thread dimensions (for example: M12 * 50 mm) Inside diameter (for example: 50 mm - the distance between the legs) Inside height (for example: 120 mm)