Many people will use this as a system of backup, while others will use it as the main storage device for their system - be it a phone or a netbook - installing their programmes and applications onto it and then running them straight from the card with no need to ever remove it. An alternative form of additional storage that many people use is the portable hard drive. These are very different devices that plug into a computer or a laptop normally via a USB cable and that way enable you to back up usually the entire contents of your computer. This is the most expansive form of external capacity, but it is not as flexible as a SanDisk Extreme Pro CF or other models of SD card. While a portable hard drive provides more space for your storage, it also requires installation and a USB port. With a SanDisk Extreme Pro CF you will find that you can go up to any computer that you encounter, and then just insert the card and start transferring files - very useful for working on the go, for uploading documents, or for sharing files with other people. At the same time many devices simply won't be able to use a portable hard drive. For example if you want to add extra storage to a phone or to a tablet, then you won't be able to do this unless you have an SD card as they don't have USB jacks or the software to run an external hard drive. Of course a SanDisk Extreme Pro CF is also far more portable than a portable hard drive. While you can easily store a portable hard drive in a bag or in a pocket, unlike an SD card they won't just fit into your wallet, and you will feel the slight weight. They would also bang around a bit which isn't much good for them. While some are called portable hard drives then, they are more just external hard drives, meaning that they are best used plugged in next to the computer and kept in one place to back up files. An SD card however is best used being carried around and quickly transferring files between different devices. If you need more space - you can always just purchase more SD cards too. So they really both have different uses, and while they both provide storage that is really as far as the similarities go. Thus if you want to have the very best storage both for the back up and the transfer of files - then you should have both systems set up for use. This way you will be able to use your flash card whenever you need to transfer information, but can keep it more permanently stored on your portable hard drive for files that need a very secure system of back up or that are too large to store other ways. There are other forms of storage you can use too and these too can offer a range of different benefits. SanDisk Extreme Pro CF is a great memory card. To benefit from the best back up you should own a memory card and a portable hard drive. Follow the links for a SanDisk Extreme Pro CF.