Have not clue what the “filter” is called!!!

[Dsmooth7]

Trying to finish the rebuild on my 231 v6. I have not idea what this “filter” is called. The mechanic told me it’s not the right size anyone know what this piece called?

 

[awdblazer]

i dont think that is a filter but a vacuum switch

 

[pontiacgp]

hows does your mechanic know it is not the right size if he/she doesn't know what it is??.......

it is a thermal vacuum switch

 

[airboatgreg]

Thermal Vacuum Switch. Find a new 'chanic