Technically, all external hard drives are portable. But some are clearly built to be placed in a backpack, pocket, or purse. These tiny external drives can aid any road-warrior or coffee-shop fanatic in storing large amounts of data in a small package.
To a degree, all external hard drives are portable. You can simply unplug them from a PC and go. That said, some are obviously more portable than others. Massive 2TB drives are large and heavy, and many large drives require an extra power source in addition to the power received from a USB connection. Such large external drives are not a hassle when transporting them from one room in your house to another, but they're too unwieldy to throw into a backpack or briefcase.
That is where portable external hard drives come in. These smaller drives are typically only a little larger than a Blackberry and weigh less than a pad of paper. They also can be powered from a USB connection. Their capacities are less than more sizable drives, but they're still capable of holding many more files than the typical ultra-portable notebook.
Transcend is often considered a second-tier maker of PC storage products, thanks to a lack of fancy high-end products and a marketing department which seems to consist of one guy in a basement office. That said, Transcend's products offer good value to those that want a basic, no-frills option with respectable performance. Such is the case with the StoreJet 25f, an uninspiring little black hard drive which could be easily missed when sat next to any modern PC monitor or tower desktop.
The StoreJet 25f's main claim to fame is performance for price. Tests indicate that the StoreJet has read and write speeds of up to 25Gbps, which is more than average for this class of external hard drive. This means backing up your files will be less of a hassle, and that the drive will feel quicker during everyday use. In addition, the Transcend StoreJet can be purchased at numerous retailers, including Wal-mart, for between $80 and $90 dollars. This is comparable to many other external drives, but those drives are slower.