Raspberry B PLUS compatible (on the first 26 pins of the GPIO corresponding to the Raspberry Pi B). This Stacking Header makes it possible to use Raspberry Pi B shields/cards directly and easily on your Raspberry B PLUS :-) See this example.
Extra long connector for older Raspberry-Pi (26 pins - stacking header)
Stacking several shield/plate, breakout, etc on a Pi is not easy if you don't have a proper Stacking Header. This Pin-Header is cut for the Pi with its super high female connector (to fit on the GPIO Pi) and extra long pins (male) to connect a ribbon, another "shield", a Pi-Cobbler, etc.
With this connector plugged into the Pi GPIO, you are just above the USB connector (~0.5mm) and above the Ethernet connector (~1.5mm). The Jack and RCA connector are even lower (>3mm).
The 2x13 pins are extra long, 9.7mm, which means that there is still 8mm when a card (1.55mm thick as standard) is "installed" on the Stacking Header... so what to connect another connector :-)