Metal flashing is a type of protective material that is installed on roofs and other building components to prevent water from entering and causing damage. Flashing is typically made of aluminum, copper, or galvanized steel, and is installed around roof penetrations such as chimneys, vents, and skylights, as well as along the edges of roofs and at transitions between different roof surfaces. The process of metal flashing work involves measuring and cutting the flashing material to fit the area to be protected, and then securing it in place using nails or screws. The flashing is then sealed with a waterproofing material such as caulk or roofing tar. Properly installed flashing can help to prevent water damage and prolong the life of a building's roofing system. Metal flashing work is typically performed by roofing professionals who have the necessary tools and expertise to complete the job safely and effectively.