Western Digital has introduced its new Mac-formatted My Passport Studio Portable Drives.

Designed for Mac users on-the-go, the drives are equipped with both FireWire 400 and USB 2.0 interfaces, a capacity gauge, shock-resistant enclosure, and include a soft drawstring carrying bag for protection.

Offered in capacities of 320GB and 250GB, the drives weigh less than 5 ounces and have an "elegant" silver metallic finish that compliments the newer design of Apple's laptop range.

The drives can back up a Mac machine using the Apple Time Machine backup software utility that comes with the Leopard OS.

WD's My Passport Studio portable drives are available now at select retail stores with pricing info provided in a curiously international format with the 250GB priced at £133.99 and 320GB $219.99 USD.