Locks in the first row of siding around the perimeter of a building, making it easier to ensure a level installation. Makes it easier to ensure horizontal installations of Maibec regular and em+ siding are perfectly level. Eliminates nails on the first course of Maibec em+ siding installations. Optimizes air circulation behind the exterior siding across the entire surface. Allows any water behind the siding to drain away freely. Prevents rodents and certain insects from infiltrating behind the siding