Simply Put, OSI Quad Max interior and exterior siding, window caulk delivers the toughness that really makes a job last. By providing superior protection against air and moisture, it gives you zero reasons to worry about a job once you've done it right the first time. QUAD® MAX is color matched to leading siding and window manufacturers' color palettes to ensure the perfect match every time. QUAD® MAX is a professional sealant for window, door, and siding that offers maximum durability and maximum application performance for use in any condition. See why OSI QUAD® MAX exterior window caulk is ideal for wet surface application under the most extreme conditions. From siding installation to windows, OSI has you covered to withstand the elements.