Rancilio Bottomless Portafilter with Triple Shot BasketRancilio Bottomless Portafilter with Triple Shot Basket Bottomless portafilters are used as a diagnostic tool to improve espresso extraction because it allows the operator to see how evenly espresso is flowing out of the bottom of the basket. Fine tune your barista skills with this unique portafilter. This portafilter, also called a "naked" portafilter, lets you identify off center extractions, multiple steams, and spritzing, among other issues and