Perfect ridge filling base coat for use with regular nail polish. I discovered this product at Sally’s Beauty Supply about 15 years ago and have used it exclusively ever since. I find applying it in as thin of coats as possible works best, doing 2 coats for most nails and 3 for deep ridges. It is a slightly thicker formula but still easy to use. It dries down matte which provides the perfect surface and best adhesion for nail polish. It also protects the nails from staining, but I wouldn’t say it does anything to add strength. I do find it helps keep polish from chipping.