Anti-DVT 'pedal' cushions

[outofsynch]

I am travellling long haul with pregnant wife, who would like to try newly devised cushions that alleviate DVt. They are designed with two chambers that you can press alternately with the feet for 'in-seat' exercise... Anyone else heard of them and or know the source?
Many thanks for any replies.

:confused:

[outofsynch]

thanks to johnr... information received.
No further replies required. Thanks