Mini Boy UV protective UPF 50 sun suit Short Sleeve in blue and lime from Rip Curl. Quick drying super soft fabric. Rip Curl ensure that all their materials are laboratory tested and are certified as having a 50 UPF rating, which is the highest protection rating available for fabrics. Standard summer fabrics often have a UPF rating of around 6. UPF stands for Ultraviolet Protection Factor. A UPF rating of 50 will usually block out 97.5% – 98% of UV, which are the harmful rays produced by the sun.