If you buy an Ebay special from China and it doesn't work you are basically out of luck. Shipping it back or trying to get money back is tedious at best. Experienced that.
If you buy from Auber, you pay more but get support and someone who will make it good. I blew out two SSR's and he sold me replacements at half price to help me recover from a disaster caused by Ebay China components that failed and caused the blow out.
I can't help but promote his good deed.