What is SPF? SPF stands for sun protection factor. This rating is used to determine how sunscreens block UVB rays. SPF 30 blocks 96.7 percent of UVB radiations, and SPF 50 blocks 98.6 percent. Let's discuss SPF in more detail. Here are some examples. What are the advantages of SPF? https://www.topscosmetics.uk/product-category/skincare/moisturisers/spf-moisturisers/