Copper Mesh for rodent exclusions and rodent-proofing. Copper Mesh is tubular, laid flat, and rolled for easy storage and use. Great when used in combination with Todol closed-cell, expanding foam. The copper mesh or gauze is approx. 5" wide (not stretched), and has an approximate diameter of between 4-5". With stretching both of these dimensions could be much larger. Tie It Up in Knots Say you have a pipe or conduit coming through a wall or floor and small pests are entering the structure through the gap between the hole and the conduit. (Cockroaches under sinks, mice at exterior walls, slugs in gardens etc.) You can just take Copper Mesh and start filling the void a little at a time but somebody came up with a better idea!