A set of mechanical bases placed on the machine table, ensuring reproducibility of laying the material (usually plates). The operator, when placing the material on the table, slides it up against protruding pins, so that the material is placed in the right position each time in reference to the program. This solution helps in high-volume production.
Available options:

Manual Pins - the operator places them in special sockets, and after placing the material manually removes them for the time of processing

Automatic pins - pins automatically come out of the table, and after starting the machining they hide to avoid collision with the tool.