This is a 2x20 header with female socket (2.54mm pitch) on one end and through-hole pins on the other end.

The female socket is 8.5mm tall and the pin part is 3mm tall. Overall, this header is 11.5mm tall.

It can be used specifically if you are making a custom add-on board or a HAT (Hardware Attached on Top) for Raspberry Pi board with 40 GPIO pins.