Piz Buin 1 Day Long photostable sun filters and patented technology provide your skin with long-lasting protection from the sun and from UVA/UVB rays, helping to prevent sunburn and ageing caused by exposure to the sun. Allows gradual tanning. To use: Apply liberally 20 minutes prior to sun exposure. One application is sufficient for a day"s exposure in the sun (Piz Buin recommend that 1 day = 6 hours exposure). Always re-apply if in any doubt, or if you have sensitive skin, or as you feel is necessary.