We've seen SD memory cards appearing in everything from toy robots to high-definition video cameras, but Logitec Japan 's latest device represents the first time for one to appear in a devious conversation-recording add-on for domestic phones.

The ¥5,000 (£21) Logitec LIC-TRA056SD doesn't necessarily need any external storage as it comes with 128MB of its own, which is sufficient for 56 hours of underhand recording. Throw in a 2GB card and you've got yourself 856 hours of subterfuge.

Security conscious

Logitec reckons businesses will find the device invaluable for keeping tabs on staff-client conversations and so has included a USB port for offloading stored recordings to a PC, for which it has thoughtfully provided the software.

To prevent unauthorized leaks, the recordings are all encrypted with a password, without which they can't be played. Once unlocked Logitec's software also allows data to be converted to either WAV or MP3 files for easy listening during those fascinating gym sessions.