The screen is, as someone else pointed out, an SSD1306. There are no sprites available. To get a decent update speed, the I²C clock has been pushed up to 800KHz rather than the default 100KHz.

The combination of a transparent OLED display, Arduino Nano Every microcontroller, HC-05 Bluetooth module, and a small LiPo battery results in a functional and versatile piece of wearable technology.