The matrix LED use a driver IC MAX7219/7221. It has a built in clock so they multiplex the LED. This matrix LED can connect up to eight 8x8's together (or a combination, such as four 1.2" 8x8's and four 7-segments, etc) on a single I2C bus.
Item weight: 12.1 g
Matrix LED 8x8 module.
Driver - MAX7219/7221
8x8 / 1.2" 32x32mm / I2C / MAX7219/7221