Larger 4 digit Serial 7 Segment display which has capability of communicating through SPI / I2C / serial TTL inputs. Smaller version is basic display board with 0.56" display and LEDs for colon and Apos. Larger board is based on same basic design but it adds ports for DS1307/DS3132 RTC boards, ESP8266-01 or 12E/F, DHT11/22 enviromental sensor, LDR light sensor and extra status LED's. Unused pins from 12F are fed into extra headers for other sensors. reference https://github.com/sparkfun/Serial7SegmentDisplay