MAX7219 is an integrated serial input/output common-cathode display driver, which connects your microprocessor to a 7-segment digital LED display with 8 digits. Only three IO ports are used to drive the eight digit display, works with 3.3 and 5V logic.
Based on TM1637 IC this module needs only two pins to control 4-digit LED display. It's perfect for time display, works both with 3.3 and 5V logic, display brightness can be controlled in 8 steps and turned on and off. Dimensions: 41.8x23.7 mm.
It's four 8x8 red dot matrix modules combined, controlled over SPI. Operating voltage is 5V, logic voltage is 3-5V, module dimensions: 12.8x3.2x1.3 cm. Comes with 5x 150 mm F-F dupnt wires.