I had recently bought an Asus 120hz monitor to play games on through my Alienware 13 R3 laptop and could not figure out why it would not give me an option to run it at 120hz. After much research, it turns out I needed an active dual link DVI adapter to mini display port. So I bought an Apple one and that didn't end up working so I bought this one. I plugged it in and it worked. It gave me several options to run it in 75Hz, 100Hz, 110Hz, and 120Hz. Yes this is pretty expensive but it is worth it if you're looking to run your laptop to any external monitor that supports 120Hz or more.