Dongles or Blue Tooth Dongles are not what your after me thinks, they are used to Blue Tooth devices to a Putter and each other and are unable to store Info.
They are similar in size and looks which is why people get confused

You need to get yourself a USB Flash memory Stick and they come in various sizes from 256MB to 32GB and probably bigger, There moving as fast as the rest of the Putter industry.

They are called various different names like Gig Stick, Flash Drive, Memory Stick etc.

They are the easiest, Neatest, And quickest way to store, Backup, And move Files, Pictures, Music etc.