The peen of a straight-peen hammer is

Its movable jaw moves parallel to the fixed jaw

The bench vice is called as parallel jaw vice because its movable jaw moves parallel to the fixed jaw

Phosphorous bronze

Tool steel

The jaw plates of a bench vice are made of Tool steel

Holding the pins

The pin vice is used for holding small diameter jobs. It consists of a handle and a small collet chuck at one end. The chuck carries a set of jaws which are operated by turning the handle.