NPT NF6MXB21 Mixed Size Nightfall Glass Tile Blends Azure Black- Indulge yourself in the uncommon brilliance of glass mosaic tile – frost proof quality that will last a lifetime. Matching 90° Glass Trim tile for steps, spas, spa steps, spillways, infinity edges & swimouts available for most glass tile blends. Ideal for steps, spas, spa steps, spillways, infinity edges & swimouts.