This high SPF technically provides you with 30 times your natural protection and will not drip or run into the eyes and sting when perspiring. Perfect for runners, golfers, cyclists, snow skiers and outdoor enthusiasts. SPF 30 Water resistant Sunscreen should therefore allow you to stay up to seven and one half hours (30 x 15 = 450 minutes), under normal sun conditions, before seeing a response to sun exposure. Re-applying product is minimized due to its water resistant formulation.