All SolRx products, including the SPF #44, #35 sunblock lotions, SPF #35 Spray-Dry, SPF #40 Dry Zinc, are made using WaterBlock®, the industry's top rated waterproofing system. This system has been through the industry's 8 hour waterproof multiple times, in different formulations, and yields 97-100% effectiveness AFTER 8 HOURS on the wearer, even with 6 hours in the water. Other sunblocks use a standard 80 minute test and as you read their labels, you see they need to be reapplied after getting into water, perspiration, exercise, etc.

The SolRx difference is in WaterBlock®, which will hold product in place through swimming, surfing, triathlons, and just about any water or sports activity. Not only will the product function better, but also it becomes less expensive to use:  one daily application versus multiple applications for "brand x"