Lexar JumpDrive Mercury review: Lexar JumpDrive Mercury

Lexar's JumpDrive Mercury flash thumbdrive distinguishes itself from the pack with a feature that is so useful, it's a wonder we haven't seen it before: an external capacity meter. USB flash drives are a handy tool for transporting small or not so small amounts of data, and they're so cheap, you probably have at least a couple of them rattling around in a desk drawer. When faced with the situation of choosing one to throw in your purse or pocket, it can be a crapshoot to figure out which one has enough space for your needs that day. For the most part, the only way to figure out a drive's available capacity is to plug it into your computer, which may entail powering up your machine and waiting for your OS to load. Lexar has solved this issue by putting an easy-to-read capacity meter on the case of its JumpDrive Mercury thumbdrive. It comes in two capacities: 1GB and 2GB. Its read/write performance is a bit uneven, but overall, we really like this product for the brilliant capacity meter feature.

Lexar's JumpDrive Mercury is tiny and lightweight, as thumbdrives should be. It's about the length and width of a pack of gum, though it's about half as thick. The ends of the silver-colored drive flare out a bit, and there's a hole in the cap for looping a lanyard through. The front of the drive has a long, narrow window, marked off in increments of 20, up to 100 percent. As you fill the drive, the capacity meter will adjust to reflect approximately how much space you're using. The capacity meter is made by a company called E-ink, which makes electronic paper. Because the meter is nonvolatile, it doesn't require a battery or external power to maintain its readout. Additionally, the meter doesn't require software on the host computer, as everything it needs is contained on the drive itself. Also preloaded onto the drive is Lexar's Secure II software (for PCs and Macs), which uses AES 256-bit encryption to protect your files. The Secure II software lets you create password-protected partitions called Encrypted Vaults. Any file you drag into the Vault is automatically encrypted. Secure II also has a file shredder that renders deleted files unrecoverable.

The 1GB JumpDrive Mercury gave an uneven performance in our anecdotal data transfer tests. It took about 5 minutes to write a 406MB folder of mixed file types to the drive but just under a minute to read it back. Of course, your results will vary depending on your system and the types and sizes of files you're transferring.

Lexar backs the JumpDrive Mercury with a two-year warranty, generous for a USB thumbdrive. (The capacity display is covered for only one year.) Free phone support is available on weekdays from 7 a.m. to 5 p.m. PT, though you'll have to pay toll on the call. Fortunately, Lexar's Web site also gives you the option of chatting online with a live support person 24/7. The site has FAQs, downloadable drivers, and a link to e-mail tech support.