comfortable and Efficient
This mask is great. The shape makes it easy to fit any kind of face. It is the most comfortable face mask out of 4 different KN95 bands I have used. According to "International Assessment Results – Not NIOSH-approved" at CDC site below, https://www.cdc.gov/niosh/npptl/respirators/testing/NonNIOSHresults.html, the maximum and minimum filter efficiency for this mask (Shandong Shengquan Willow leaf-Shaped Respirator) was 98.79% and 98.11% based on evaluation of 30 sample masks.
Also, you should adjust the ear loops to make sure the mask fits tightly if you have a small/medium face.