I think this is the best product in online for health care. I bought 3 in 1 vaporizer. It is very useful to me and best quality compared to market products. And the price is also less comparing to market. These products are available in all online shopping at low cost. And the product will be on time delivery as mentioned while purchasing. Regarding usage and maintenance, we can contact customer services. Not only this product, every product in health genie is good.