Northern Lights™ - This MOVING COLOR™glass tile continually changes as the heat exposure changes. Inspired by the stunning Northern Lights® of Alaska, this line features 4 x 4 glass tiles that appear black at room temperature and move through the color spectrum when temperature (warm water, radiant heat, etc) is applied. The moving color is dynamic to the temperature of the heating agent. Watercolors® is a unique MOVING COLOR™ line closely resembling the luminous quality of water color. The tiles shift from a base coat of color to colorless when exposed to heat. These 4 x 4 glass tiles are currently available in 8 colors. The color change is “reversible,” i.e., the original color will be restored upon cooling. • The MOVING COLOR™ glass tiles are waterproof and can be used for any kind of water installation. • At this time, we recommend interior applications only. • These glass tiles possess moving color and will experience color variation over time. Reaction life of moving color has been witnessed as exceeding 7 years. • All MOVING COLOR™ glass tiles are backed with a limited one year warranty.