This five-layer anti-viral mask with high bacterial and particle filtration efficiency is a must-have for sure. It has 95% efficiency with an additional filter for extra protection. It comes with concealed nose wire for a better fit. People with any lung or heart conditions should consult with their physician before wearing a Mask. Stop using the product if you experience any difficulty in breathing while wearing the mask. Each filter can be used for a maximum continuous period of 6 hours.