Very good, it really eliminates odors and the valve is very convenient, allowing for use for hours without feeling suffocated.
The only flaw is that the rubber attachments are fastened with staples that easily rust (if the mask is closed in a bag for protection).

This mask is only evaluated for the use it is intended for and not for the coronavirus.
It is an excellent mask for what it is designed to offer, with a perfect fit on the nose resulting in no fogging of work glasses.
In a dust cloud that I have worked in several times, nothing passes through

Let's clarify something.
The mask is one of the most successful in the Greek market, for many years now, and it is aimed at protection against dust (e.g. abrasion in furniture workshops). The retail price was around 4 - 4.5 €. What makes it a best seller is the activated carbon filter that encloses and absorbs odors. It is recommended to wrap it in a bag when not in use to prevent the activated carbon from "losing its effectiveness" unnecessarily.
Apart from that, regarding the coronavirus, it is correctly not allowed by the government because it has an exhalation valve, and your pocket rightly does not allow you to spend 80 € + shipping that I see at the moment.

Update (9-12-20): Finally, the price has returned to normal levels.