- GPIO expansion: converts one ESP32 GPIO into two outputs, making it easier to reuse pins across projects and on a breadboard. - Double-layer PCB: a two-sided routed design with one pin connected on both sides to enhance circuit stability and signal integrity, reducing the chance of poor connections and unstable transmission. - Compatibility: only suitable for the 38PIN narrow version ESP32 without mounting holes; not compatible with other ESP32 versions. - Connection options: two types available – Pin Header and Screw Terminal. Just choose the option that fits your setup. - Use scenarios: suitable for prototyping on a breadboard when you need two drives from a single GPIO (for example two indicators or sensors); distributing a signal to two modules during testing; convenient for modular development projects requiring pin duplication.