Riemann p20 is a very high quality once a day sunfilter giving ultra high protection against the suns burning uvb rays whilst at the same time letting through the uva rays that are needed to allow you to tan riemann p20 is an spf20 providing 20 times your own natural protection against the sun apply only once a day for all day protection p20 retains around 90 of its protection even after swimming frequently throughout the day odourless and non greasy quickly absorbed by th