Hi, you may find these links helpful:
http://www.diabetes.co.uk/diabetic-products/circulation-booster.html
http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=37534
One of these products was subject to a ruling in Australia that the distributor could no longer claim the product improved circulation because this had not been scientifically demonstrated. That doesn't mean it doesn't improve circulation, just that it hadn't been demonstrated. There is good evidence that TENS therapy has some effect, and this may be similar.
I think if I had the kind of symptoms this product might be able to treat, I would be prepared to give it a go, especially if I could find a product with a 3 month money back guarantee.