5/16"-24 x 4" Zinc Plated Grade 5 Steel Fine Thread Hex Cap Screws

Diameter: 5/16"
Length: 4"
Material: Steel
Finish: Zinc
Head Style: Hex (1/2" Wrench)
Thread Size: 24 (Fine)
Thread Length: 7/8"
Hardness: Grade 5
Type: Cap Screw

Box of 8.

A hex cap screw has a hexagonal head, designed to be driven by a wrench.