This aftermarket Breville bottomless or naked portafilter will fit Breville Barista (Touch, Pro, Express), Bambino Plus, Infuser and Duo Temp machines.

Taste the difference this Breville bottomless portafilter can make. The Barista can watch the coffee brew right from the bottom of the filter basket and immediately know if channeling occurs, signaling that a level tamp was not made, which makes this an invaluable tool for training.  This item comes standard with a 18 gram basket, but will also accept other Breville portafilter basket.

Still not convinced that you should own a bottomless portafilter?  Have a look at this great article by Perfect Daily Grind.