Our Volumizing Keratin Brush distributes keratin fibers from the color cartridge of your choice and holds them in place with static electricity. To have the fibers last longer, you can use our holding spray or a hair spray, which will keep them in place. You can decide if you want to apply more fibers on the days after initial application, until you shampoo your hair. It may depend on the degree of thinness of your hair and also how often your touch it or brush it after using the keratin brush. Click here to order the holding spray.