- 54mm bottomless portafilter compatible with Breville 8 series BES880, BES878, BES875, BES870, BES840, BES810; Barista Touch/Express/Pro; Infuser; Duo Temp Pro; replacement espresso machine accessories. Please verify your machine model before purchase to ensure proper fit and a satisfactory shopping experience. - Material and filtration: The filter head is made of 304 food-grade stainless steel with a precision-cast professional filter screen, ensuring reliable performance with coffee grounds and fully extracting every drop of coffee essence for a balanced, delicate flavor. - Ergonomic design: ABS plastic handle with a smooth surface and ergonomic shape for comfortable, precise manual control during extraction. - Extraction visibility and consistency: The 54mm bottomless portafilter design allows direct observation of the extraction process, helping you identify issues such as channeling or uneven tamping and adjust to achieve consistent espresso. - Use scenarios: Ideal for home espresso setups to calibrate grind size and tamp; useful for barista practice to learn extraction cues and improve technique; serves as a compatible replacement accessory during routine maintenance for Breville 8-series machines.