Mass requests for protective equipment (5)
I believe the answer is:
masks
'protective equipment' is the definition.
(I know that masks is a protective equipment)
'mass requests' is the wordplay.
'mass' becomes 'm' (symbol used in Physics e.g. f=ma).
'requests' becomes 'asks' ('ask' can be a synonym of 'request').
'm'+'asks'='MASKS'
'for' acts as a link.
(Other definitions for masks that I've seen before include "Hides, disguises" , "Coverings to conceal the face" .)