Surgical mask
A surgical mask was a protective face covering used by medical staff to decrease the likelihood of cross-contamination and infection during medical procedures. They were in use until at least the 22nd century

While trying to rescue Pavel Chekov from 20th century medicine, James T. Kirk, Gillian Taylor, and Doctor Leonard McCoy wore surgical masks to blend in with the other staff members. ()

In 2368, Berlinghoff Rasmussen mentioned that he and a colleague had visited a 22nd century ship. Beverly Crusher replied that he likely saw surgical masks and surgical gloves. ()

External link 
 
Medical equipment