I bought mine from my vet. They were brilliant at cleaning my dogs' teeth - both dogs had very badly tartared teeth and were due for a dental visit but two sinews each over a week completely did the trick. They were expensive, about �5 a packet of two, I think, but saved me an enormous vet's bill. Unfortunately, despite constant requests, my vet doesn't seem to be able to get any more. If anyone knows if they can be bought direct from the manufacturer, I'd be very grateful if you'd let me know.