Dermatologists recommend that everyone protect themselves from the sun by using sunscreen, wearing closely woven sun protective clothing, sunglasses with a UV filter and, of course, a broad-brimmed sun hat. Tilley brimmed hats have been tested and certified to provide a UPF of 50+, the maximum rating given. We have UPF rated travel clothing too. Check the product page details for UPF ratings. What is UPF? Is it similar to SPF? UPF stands for Ultraviolet Protection Factor. A UPF rating is granted to apparel that has been tested and proven to block a certain amount of ultraviolet radiation. UPF is like SPF, except that UPF means the UV testing was conducted on fabric rather than peoples skin. An SPF rating only applies to lotions applied directly to skin, not fabrics. Tilley brimmed hats & some clothing are tested and certified to provide a UPF of 50+, the maximum rating given.