ChirpyMBP's don't have an Ethernet port so you can use this instead of paying a small fortune for an Apple one that doesn't have anything but the Ethernet adaptor. I bought a Thunderbolt dock that has an Ethernet port, 3 USB 3 ports, and 2 Thunderbolt ports and it works great. I wish this drop was a bit later though :( 3 on that plus 2 on the 13 inch MBP I just bought isn't enough for my NI Maschine Studio, NI Komplete Kontrol S49, Livid Instruments ds1, Apogee Mac + iOS duet, and 4 slot 2.5/3.5 HDD drive loader.