Stainless and mild steel.
This harness is modeled after a number of sport jousting armours originally made by Anton Peffenhauser (spelled many different ways) in the second half of the 16th century. Because this type of armour is used without a shield the left gauntlet, called a manifer, is exceptionaly strong and is of a mitten style to better protect the hand.
The third picture is of a similar harness with the exchange pieces attached. These plates offer excellent protection to the head and neck. They also provide a good target to the opposing Knight. Also note the small fin like piece attached to the breastplate near the right spaudler. This acts as a glancing surface to prevent a lance from sliding off the breastplate and then under the shoulder armour. The grand guard and bevor (left shoulder and chin exchange pieces) were put on crooked by accident during our live joust show and we could not take time to fix them. Normally these plates would fit snug to the breast plate and helm.