I'm posting in this section because I'm not quite sure what I have here. But I have some ideas.
Here's this little stamp picturing Benito in all his bald glory.
Here's what I know.
P. N. F. = The National Fascist Party (Partito Nazionale Fascista; PNF) was an Italian political party, created by Benito Mussolini as the political expression of fascism (Wikipedia)
Operaie e Lavoranti a domicilio = workers and homeworkers (Google translate)
No denomination so it's not a postal stamp.
The left side is toned, much like between a pair Italian parcel post stamps .
So my conclusion is this is a right side tab for a pair of stamps, possibly revenue, to benefit workers loyal to Mussolini's fascist party.
Am I close?