What is SPF? SPF stands for sun protection factor. This rating is utilized in sunscreens to block rayons of UVB radiations which are the major cause of sun-related damage. SPF 30 blocks 96.7 percent UVB radiations, and SPF 50 blocks 98% UVB rays. Let's discuss SPF in more detail. Here https://www.topscosmetics.uk/product-category/skincare/moisturisers/spf-moisturisers/