This L9 steel alloy hexagon bolt has a thread size of 1/2"-20 UNR for increased resistance to fatigue. Made with a yellow zinc dichromate finish, this fastener has a Rockwell hardness of 38/42C, a proof load of 145,000 PSI, a tensile strength of 180,000 PSI, and works at a maximum temperature of 400 Degrees F. This hex bolt has an overall length of two inches with a 0.736-0.750-inch wide and 0.364-0.386-inch thick head. This item must be purchased in multiples of 50.