Stuf-Fit Copper mesh is a kind of knitted wire mesh. It is designed to stuff all kinds of openings to stop pests, bees, insects, rodents and other similar unwanted animals. Once tightly packed in a hole, crack or gap, the copper mesh refused to be pulled out. This copper wool has special interlocked structure. You can tack it, staple it or glue it to any openings. Compared with steel wool, copper wool has two advantages. First, its knitted construction often catches rodents' teeth and makes it hard for them to chew through or remove. Second, copper mesh never rusts.