Cotton masks with a manually added filter were as effective as government-certified masks in blocking particles of human saliva, research by the Seoul Research Institute of Public Health and Environment showed today. The average particle collection efficiency of cotton masks with electrostatic filter cotton attached inside was found to be 80 to 95%(Handmade), while government-certified...Read More
When you book with an account, you will be able to track your payment status, track the confirmation and you can also rate the tour after you finished the tour.