It is a retrofit product which can be installed after construction. Once again it is designed to prevent pest entry and provide screening for embers. It is easily installed with the (black) plastic applicator that comes with each pack. The flexible fringes bend as the screen is pushed into the weep hole, creating friction with the surrounding brick and mortar. This friction fit means the screen is left firmly in place and fills any uneven spaces around the edge of the weep hole.