Portola’s Matte Wall Sealer is a clear, matte finish that is non-toxic, super durable and will not yellow over time.Matte Wall Sealer is a multi-purpose acrylic matte sealer designed for use with most Portola products and finishes. Matte Wall Sealer can also be used for sealing wood or concrete. This premium quality product is formulated with ingredients that screen out the destructive ultra violet rays and can be used on both interior and exterior surfaces and over most Portola finishes.