Adafruit Prototyping Pi Plate Kit for Raspberry Pi (Fully-Assembled) for 26-pin GPIO Raspberry Pi
Normally this is sold as a kit. I purchased this, assembled it. I checked the 26 gpio pins by continuity test with DVM to pcb pads to verify my work.
This is a very high quality pcb with the usual Adafruit standards of construction. The cheap imitations you see from China are exactly the same design but not the same quality. You should visit the Adafruit web site and read all the documentation on this board, it is great! Just search for "Prototyping Pi Plate Kit" on AdaFruit and make sure you are looking at the 26-pin version..
This product only works with Raspberry Pi with 26-pin GPIO.