I2C 2-Channel 3.3V to 5V Bi-Directional Logic Level Converter

An I2C bus only ever needs two lines shifted, SDA and SCL, and this board keeps to exactly that rather than carrying four or eight channels that would mostly sit unused. It's the right size for the common case of mixing a 3.3V sensor module onto an Arduino's 5V I2C bus, or the reverse, bridging the voltage gap cleanly on just the two wires the protocol actually needs without adding board space or cost for channels the project will never wire up.