Diff Breathers

[CanukRunner]

I just replaced my rear diff breather...

the top was kinda boble head ish and moved up and down a little...

Kinda what i expected...

However, I just ordered my front diff breather... the top is fixed and does not move... it was also half the price....

I blew through it and it feels like its highly restricted but it does let some air out under pressure.. is this normal.. or should it bobble?

Thanks!