I am an I/O expansion module based on I2C interface control, which can expand up to 16 I/O ports and support the simultaneous use of up to 8 expansion modules, providing up to 128 I/O ports. It is compatible with 3.3V and 5V levels via I2C interface control, requiring only 2 signal lines to expand 16 I/O ports. The I2C communication address can be set by shorting the A0/A1/A2 solder joints. It provides two interface types: PH2.0 terminal and solder pad, and supports parallel connection of multiple I2C modules. Onboard level conversion circuit allows compatibility with operating levels of 3.3V and 5V. Working voltage: 5V / 3.3V Control interface: I2C Product size: 38mm x 23mm Via diameter: 2.0mm Color: As shown Material: PC Due to different product batches, the appearance may vary slightly, but this does not affect usage. Package Contents: 1 x Expansion Module, 1 x Cable The package includes only the items listed above; other products are not included. Note: Light reflection and differences in display screens may cause slight variations in color between the image and the actual item. Measurement error is +/- 1-3cm.