Biotrue Brand - We use elements that are inspired by the biology of your eyes – in some products even using ingredients that are found naturally in your tears! Biotrue Hydration Boost for Contacts are the first preservative free multi-dose contact lens drops. Not only are Biotrue Hydration Boost for Contacts free of preservatives but they are also pH balanced for comfort. Enhanced with HA (Hyaluronan), Antioxidant (Protects HA from free radicals), and Electrolyte. For up to 8 hours of moisture (based on a laboratory study). Helps prevent deposit buildup. Rewetting Drops for Contact Lenses. Free of preservatives.