Did not see this in a search of the Apple Devices thread so I thought I would mention it briefly:
An iOs Flash Drive by SanDisk
It can be used as a regular flash drive. When connected to your iPad or iPhone it uses it own app, free from the app store. Made primarily for photos, music and videos it also works well with epub, pdf, etc. Transfers books to the various apps on your i device similar to CC. It also will back up your Contacts and Calendar.
When connected to an ios device it works as advertised but has some limitations that I hope will be overcome in a software update of the app. For example it does not save to a cloud box but will save to the file app and then dropbox (etc.) can be used.
I bought the 128 version and find it useful. It will play music or videos or view pictures right off the drive.