Toshiba has married its card-size hard disk drive with Bluetooth wireless technology to come up with a portable storage device aimed at PDA (personal digital assistant) users who need large-capacity storage. The Hopbit will be publicly unveiled at the World PC Expo show in Tokyo this week.

The device contains a 5GB version of one of Toshiba's 1.8in hard disk drives. It will hold around 1,000 average-length MP3 audio tracks, 3,000 digital images from a 3Mp (megapixel) camera or 37 hours of Mpeg-4 video encoded at 320x240 pixels and 15fps (frames per second), said Toshiba.

A Bluetooth transceiver embedded in the Hopbit means it can be accessed from the PDA and also from other Bluetooth-equipped devices. Bluetooth's device-linking function and proprietary software should ensure that data remains accessible only to approved users, said Toshiba.

The Hopbit B105H will go on sale in Japan from 1 November and will cost ¥50,000 (£258) making it an attractive option for PDA or mobile PC users who want extra storage space at a low cost. A similar investment in SD (Secure Digital) memory cards would buy around 512MB of storage (in 128MB cards), or around one-tenth the space offered by the Hopbit.

The device measures 110x70x22mm and weighs 180g. A rechargeable lithium-ion battery should allow the Hopbit to run in standby for around 200 hours or in operation for six hours on a single charge.

Toshiba has no plans at present to put the Hopbit on sale overseas although the company will consider it if it's a success in the Japanese market, said Midori Suzuki, a Toshiba spokeswoman.