Living seamlessly in the menu bar Mountain allows you to manage volumes with ease.
With Mountain you can mount, unmount or eject volumes with two single clicks. Unmount a single volumes or eject all external volumes at once. Unmounted volumes will be spinned down and can either be unpluged or reactivated in Mountain without the need to unplug the USB cable and plug it back in.
Mountain identifies applications that block volumes from being ejected and allows you to quit them right away.
OS X 10.6 or later.
Mac App Store: https://itunes.apple.com/app/mountain/id528726140?mt=12