Reviber - excellent product, excellent service.
Thoroughly recommend Reviber. Bought it for my dad who suffers with lower back and leg muscle problems and therefore spends a lot of his time in a sitting position. Machine arrived very promptly, was easy to set up and he loves it! Great for his circulation; he uses it little but often (5 mins a time 3 or 4 times a day). He says he's really noticed a difference in his legs and it is so convenient and easy for him to use any time he wants.