Drip edge
Metal flashing along roof edges that directs water into the gutter.
Drip edge is the L-shaped metal flashing installed along the eaves and rakes of a roof. It guides runoff into the gutter instead of letting it wick back under the shingles and rot the fascia and roof deck. Missing or damaged drip edge is a common cause of rotted roof edges and overflowing gutters, and most building codes now require it.