It is very difficult to the get the batteries for this type. I have had to visit a couple of distributors and the dealer who sold it, only to be told that they do no have ready stock of batteries. Suggest do not buy this product. Or else get two or three batteries, when purchasing a new unit to save the trouble. The purification is good. The call line will take your requirement, but by the time you get the spares, 10 days would have passed.
Otherwise it is a good product, if you are able to tolerate the poor after sale service.