These jaws are designed for use with the Fireball Hardtail Vise (the big red one).
6.5" Serrated Jaws are standard jaws that ship with the hardtail vise. Sold as a pair of 2.
6.5" Smooth jaws are hardened, and feature a 3/32" height and 3/32" depth ledge for low profile work holding. Sold as a pair of 2.
6.5" Smooth Aluminum Soft Jaws. Sold as a pair of 2.