Hi Marco, the power supply works with Surface Book and Surface Pro 3. - Tested. I assume that it also works with Surface Pro 4. I don't have a Surface Laptop, so I haven't tested it. It certainly doesn't work with Surface Studio. - One difference: In the original, the plug has an additional USB port, but the packing size is smaller with this plug. Best, C.

I have a Surface Pro 3 and with this power adapter I can only charge the device when it is switched off. I wonder if that's healthy.