Helmsman® Spar Urethane is a specially formulated protective clear finish for exterior or interior wood that is exposed to sunlight, water, or temperature changes. It contains UV blockers to reduce the sun's graying and fading effects. Helmsman® Spar Urethane forms a protective barrier against rain and moisture and its special oils allow the finish to expand and contract with the wood as seasons and temperatures change. Helmsman® Spar Urethane is not recommended for use on floors.