This very nice, durable mat is embedded with superflat EL wire that lights up brightly to proclaim your "Welcome". During the daytime, the "Welcome" is a prominent green color, but as soon as it gets dark, the automatic light sensor activates the EL technology to illuminate the lettering. EL technology lasts for many years, is cool to the touch, uses minimal electricity, and never needs replacement bulbs, making it perfect for use in this doormat. The mat itself is a durable black astroturf-like material. A small cord runs from the mat to a light sensor and power unit that plugs into any standard 110v U.S. style outlet. (Be sure to keep the power unit away from water or rain.) The mat is a large 25.5" x 16" size.