P20 is designed to ensure that one application a day is sufficient keeping the time spent applying and reapplying sun protection to an absolute minimum p20 is proven to work for up to 10 hours1 due to a very stable formulationp20 is proven to remain effective in the water even after frequent swimming throughout the day p20 retains the same protection category as before entering the water which is unique for a sun protection product in fact p20 has been categorised as very water resistant2