What does F593C mean?

The F593C marking means the bolt was made to meet an ASTM standard defining what it’s made of and how strong it will be. A superior bolt then the common hardware store bolt. All the best, Robert Gainer. D.

What size is bolt F593C?

ABP F593C-304 Stainless Bolt, 1/2″-13 x 2″, 1.30″ Thread Length, New | eBay.