Choose a big brand, such as American 3M, the pre-filtration is better, the standard is higher, and it is more comfortable to use, but at the same time the price will be much higher. However, choosing the right place can still offer a lot of discounts! For example, there is a group buying meeting in Beijing called Easy Pack, where the price of 3M pure water will be several hundred lower than that of the activities in the store, and you can also enjoy the after-sales service in the store, which is quite affordable. Only by using pure water will you know how much the quality of life will be improved.