Once-a-Day means what it says, you apply the lotion once, preferably after a shower 15 minutes before you expose yourself to direct sunlight; and the protection lasts all day. All the range has been dermatologically tested to ensure that no problems occur with regular use and to show that it meets the U.V.A and U.V.B requirements, having a 4 star U.V protection of Superior you know Once-a-Day is high quality. Once A Day Protection SPF 20 gives the family the freedom to enjoy the day in the knowledge that they are totally protected. 200ml