I ordered 3 HHO units from Hydrogen Assist Development (www.safehho.com), spending $1, 800! To date, I have not received but 1 incomplete unit. I have repeatedly asked for a refund, but have not gotten it. They have a warranty and a guarantee but it is bogus. I paid via paypal but they will not help because I "received something." Yes, I did receive a partial unit but I ordered 3 complete units. Paypal does not care if I received what I ordered or not because it did not go through ebay. What? Who cares if I didn't buy it via ebay? read full review »