What is standard faucet thread size?

Thread of aerator is depend on faucet design

For faucet design, there is difference between American market and European market

For American market, they use American thread which is Female 55/64-27unsd-2b,  Male thread 15/16-27uns-2a, also have dual thread which is 55/64-27unsd-2b&15/16-27uns-2a

European market also defined by Female thread and Male thread, but it use metric thread standard

For Female thread they usually called M22 , and for Male thread they use M24

So depending on this kind of situation

For American market,  usually need to supply Female 55/64-27unsd-2b faucet aerator and Male thread 15/16-27uns-2a faucet aerator 

For European market and Asiz market,  need to change  to M22 faucet aerator  and M24 faucet aerator

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