ZAR ULTRA Exterior polyurethane is an incredibly fast-drying, oil-based, clear wood polyurethane finish that dries in only 2 hrs. Formulated with UV radiation absorbers and antioxidants, it's specifically formulated to protect exterior surfaces that are subjected to direct sunlight. ZAR ULTRA exterior polyurethane is ideal for wooden marine surfaces that are located above the waterline, exterior doors (fiberglass and steel), patio furniture, fences, gables and other wood surfaces exposed to extreme, harsh weather.