Head type: round, square, hex,"T"

Neck of the bolt: cylindrical, oval or square

Thread: UNC, UNF, ISO, BSW

Diameter: M16---M30, 7/16"---1-1/2", the length does not limit.

Grade: 4.8, 5.6, 6.8, 8, 8.8, 10.9,

Finish: Blacked, Black phosphorization chrome-faced. Zinc plated, (white, yellow) hot dipped galvanized, plain and so on