I had to have a Google and think they are called FFP3, they do create a seal but you have to have your face measured, but it looks like in medical settings they are disposable. You can also just buy them online for yourself but they are supposedly only super effective if you have your face measured and buy your specific fit which is what they do in medical settings.My apologies, don't know what you mean, do you have a link to them?
What kind?
We used to get people on the thread who worked on covid wards saying they were waiting for their size to arrive so were having to wear the blue ones, and then anyone who wasn’t in the medical field who said they had bought FFP3 masks got a slap on the wrist for buying them and causing supply issues.
Lockdown 1 thread drama history for you there shoutout those who also remember the great B&M divide of Jan 21.