Due to the outbreak of COVID-19,Our warehouse in California was forced to close， we were forced to ship from China instead of the United States, but the current international logistics shipment speed is very slow！Make sure you can wait 25-35 days or more days delay for shipping before you order
Generally, the time recommended by the laboratory that helps us test the filter is 100 hours, but we think it needs more detailed classification!
1. Woodworking -- it is recommended to replace the filter every 4 hours
2. Cleaning - it is recommended to replace the filter every 6 hours (do not reuse the filter)
3. For daily wear or immune deficiency diseases such as lupus erythematosus, it is recommended that you use it for about 100 hours.
4. Just for decoration or sun protection and warmth preservation -- no filter is needed
5. Patients with pollen allergy - need to replace the filter once a day when wearing
6. Urban pollution, such as automobile exhaust - replace filter every 2 hours
7. Pubs, nightclubs and other public places for smoking -- change the filter every 4 hours
8. Cold patients -- it is recommended to use our disposable masks
Our policy lasts Free return within 30 days, free replacement within 180 days. If 180 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange. （KN95 masks and disposable civilian masks Not applicable）To complete your return, we require a receipt or proof of purchase.
Handing time:24 HoursShipping time:7-15 days