Mamy now you've got me wondering. This is what I got but looking at it, it would seem not to recognise the number Sue gave and that was when I clicked on the actual Dogwell website.
Amazon.com User Recommendation
fkmr0&keywords=dogswell+dw998n
Anyway, Wolf is right, it's a punishment whichever shock it gives. Such a shame Sue is unwilling to discuss with people who have the dog's well being at heart. I have fostered for several dog rescues over the years and they would not rehome a dog where one of these devices would be used. At the risk of being jumped on, I would describe it as on the verge of abuse if not actual abuse.
I hope Sue reads Victoria Stilwell's link and changes her mind. There are kinder ways to train a dog, whatever the problem.