The FlyWeb Glue Boards come in two colors: white or black. The color you choose is a personal preference. The black color is more discrete and will hide any caught flies (better for homes and dining rooms in restaurants). The white color makes caught flies more visible, which is better for monitoring. FlyWeb Fly Light glue boards for use in the FlyWeb Fly Trap . To activate the sticking power of your glue card, just peel away the protective plastic film and insert the card into the inside slot at the back of the FlyWeb light fixture. When the card becomes full, throw it away and install a fresh card.