The Non-valve mask offers the same filtration efficiency as the PRO mask. The filters have been rigorously tested by Nelson Labs, a US-based global leader in the field of lab testing. They have been found to have a viral filtration efficiency of 99.6%, a bacterial filtration efficiency of 99.7%, and an average particulate filtration efficiency of 99.7% down to 0.3 microns.
If you have further questions, please contact us by email at info@cambridgemask.com or Chat button on our sites to connect with our Customer Service Team.