By simply adding SunGuard to your laundry, you can transform everyday clothing into sun protective gear with a UPF protection of 30. SunGuard works by washing an invisible shield into clothing that helps block more than 96% of the sun's harmful rays from reaching your skin. With the active ingredient TINOSORB FD, a UV protectant from Ciba Specialty Chemicals. SunGuard can boost the UPF protection of a white cotton T-shirt from UPF 5 to UPF 30. SunGuard is so easy-to-use. Add 1 package of SunGuard to a warm or hot water laundry load along with laundry detergent and you wash in skin protection for up to 20 washings. SunGuard won't change the color or comfort of clothing and is safe for even the most sensitive skin.