https://youtu.be/UY7KAnJGYwY
Never seen them used, but I do remember my teacher telling us his experience with al stick rods - short shelf life and corrosive flux coating damaged his shelf. Welds sucked. Use as last resort or take up basket weaving instead.
Middle rods, can't tell what they are in the pic.
Bottom rods, 612, very useful weld all maintenance/repair rods and for joining dissimilar steels.