My macbook is MD101，an optibay with Crucial M4 128g SSD, and sometimes go out or in the silence night, I don't want to use the HDD, so use this to eject it.
Not only can protect in the way of bumpy HDD, also can create a quiet environment, of course, most for me, it can save electricity on my battery... And when you want to use it, then click mount it ~
Although not many technical content, only convenient myself.
It has English and Chinese version, depend on your system language automatically.
Download zip as archieve : http://pan.baidu.com/s/1DYwQh
Open source at GitHub : http://github.com/gischuck/DiskMount