The MultiTech MTC-MAT1-B03 MultiConnect Cell Modem is a blue USB modem designed for use with Enphase Energy systems. It features tri-band connectivity and is compatible with AT&T carriers. With dimensions of 3.2 inches in length, 2.5 inches in width, and 1.2 inches in height, this modem provides a convenient and efficient solution for connecting your home networking and connectivity needs. Its compact size makes it easy to set up and use, offering a reliable and high-speed internet connection.