There are many variables to establishing a precise filter life, such as the pollution in your area. Our filters can last up to 100 hours on average and we suggest changing the filter every second week or so.
Our mask is a hygiene product and can only be returned if unopened in the original packaging. If you have opened the package and are not satisfied with our product, please write to support@mh-purar.com and we will do our very best to help you out on a case-by-case basis.
For detail information, please refer to our Return Policy.