As known as fish eye bolts abroad. Refined eye bolts, a smooth spherical surface, thread precision is high, its thread specifications are from M6 to M64. The surface treatment of the knuckle bolts are hot-dip galvanized, osmosis plating, white plating, color plating, and other anti-corrosion measures.

Knuckle bolts are widely used in low-temperature and high-pressure valves, oil drilling equipment, fluid engineering, pressure piping, oilfield equipment, and other fields, often in the detachment of the connection of the occasions or tools such as the valve industry, folding bicycles, strollers on the use of knuckle bolts due to the ease of use, quick, and supporting the use of the nut has a connection of the role of tightening, the applications are wide-ranging.