Riemann P20 Once-a-Day Sunfilter is a well tried and tested product to protect from sunburn while allowing a gentle, slow golden tan. Get prepared for when the sun does shine with this exceptional sunfilter that offers so many benefits compared to other sun creams and lotions. Riemann P20 Once A Day Sun Filter SPF20 is perfect for people who like swimming in the Sunshine, P20 Once a Day Sunfilter is simply not like any other product. It is a unique product as it needs to be applied only once a day - so you can simply get on with enjoying yourself. Active 15 minutes after application. It is a unique product as it needs to be applied only once a day - Active 15 minutes after application. There\'s no need to re-apply the product - so you can simply get on with enjoying yourself. (Easy-to-follow instructions are pr d with each bottle).Riemann P20 Once-a-Day Sunfilter pr s high sun protection - factor 20 - and is still 90% effective after swimming. P20 is remarkably good value - Once a day application means a little goes a long way and therefore it is more economical than other sun preparations which need to be re-applied regularly during the day. Not only all this, but P20 has been proven in the scorching Saharan sun and many other extreme conditions.