This consumable/spare part is for Roken type mask fitting testers.
They are used when sampling dust particles inside the mask when measuring the mask leakage ratio. They are inserted between the mask and the face.
There is no need to puncture the mask (it is non-destructive), so after using the test guide to measure the leakage ratio, if the test guide is gently removed and the seal is checked again, the worker can enter the workplace as is, without removing or wearing the mask. Accordingly, this is suitable for routine fit checks.