1. [Compatible with listed machines only] This 54mm three-ear bottomless portafilter is only compatible with Barista Pro (BES878), Barista Express Impress (BES876), Bambino Plus (BES500), Infuser (BES840), Barista Touch (BES880), Barista Express (BES870), Duo-Temp Pro (BES810) and Bambino (BES450). Not compatible with other coffee machine models. Please confirm your machine model before placing an order to avoid compatibility issues. 2. [Benefits of the bottomless portafilter] The bottomless design allows you to clearly observe the entire extraction process, helping to identify and correct grinding, distribution or tamping problems. It is a must-have for those who want to improve the quality of their espresso. 3. [Included filter for uniform extraction] The filter allows water to be evenly distributed on the coffee grounds, reducing channeling and ensuring consistent extraction. It also helps keep the machine's brewing head clean. Made of Food-Grade Stainless Steel: This portafilter is made of premium food-grade stainless steel for guaranteed durability, ensuring your espresso remains pure and unaffected by contaminants. 4. [304 Stainless Steel Double Filter Basket] The included double filter basket is made of durable 304 food-grade stainless steel to ensure pure, contaminant-free espresso extraction while preserving the rich flavor of the coffee. Design for Improved Extraction Quality: The bottomless design of this portafilter allows for better observation of the coffee extraction process, improving the quality and consistency of your espresso.