Add one package of SunGuard to a load of laundry, and you wash a skin-saving Ultraviolet (UV) Protection Factor of UPF 30 into every garment — and protect against damaging rays for up to 20 washings. You and your family can enjoy the comfort of wearing everyday clothing, and feel comfortable in the knowledge that they are better sheltered from the sun - even as they embrace the great outdoors. Sun Guard is safe for all washable fabrics including cotton, linen, rayon and silk. Sun Guard will not add sun protection to polyester or acrylic fabrics.