Review on 🔧 HCDC RPi GPIO Status LED & Terminal Block Breakout Board HAT for Raspberry Pi A+ 3A+ B+ 2B 3B 3B+ 4B" - Enhanced SEO-optimized product name: "HCDC RPi GPIO Status LED & Terminal Block Breakout HAT Board for Raspberry Pi A+ 3A+ B+ 2B 3B 3B+ 4B by Robert Hines

So far I've only used LED indicators for contacts. Haven't tried using terminal blocks yet. It has green LEDs for each of the signal GPIOs, red LEDs for the 3.3V pins, and blue LEDs for the two 5V pins. The GND pins are essentially "black" with no LED. An interesting observation is that there appear to be about 9 pins that have some sort of "pull-up" resistor connected to them, as these pins glow green when in input mode. I don't know if there is a pull-up feature on the Model 3A+ board I'm using or in the Broadcom CPU chip.