Pasquini Bottomless Portafilter Livia G4 and 90Pasquini Bottomless Portafilter for Livia G4 and 90 Bottomless portafilters are used as diagnostic tools to improve espresso extraction because it allows the operator to see how evenly espresso is flowing out of the bottom of the basket. Sometimes called a naked portafilter, it will let you identify off center extractions, multiple streams, and spritzing, among other issues and gives the best feedback for irregular distribution of the ground espresso.