Milanese right pauldron and lance rest.
Note the more open design of the right pauldron (shoulder.) This allows to the wearer to couch a lance high under the arm for more control and strength. The steel fin on the breastplate, below the pauldron, is a lance rest. It is attached by means of small steel tabs called staples. A pin passes threw holes pierced through the staples to secure the lance rest. It can be removed or adjusted easily by removing the pin.