51 MM DIAMETER: Designed to fit baskets of 51 mm diameter, this 3 ears bottomless portafilter is designed to fit CASABREWS CM5418 and 3700 Series PREMIUM SOLID WOOD HANDLE: The portafilter head is cast in food-grade stainless steel and high polished by manual, precise size ensures the portafilter is engaged in the group firmly. The portafilter handle is made of natural solid wood, solid surface and ergonomic design to ensure perfect grip and easy manual control BOTTOMLESS PORTAFILTER: The design of the bottomless filter allows for a clear and unobstructed view of the extraction process, making it easier to identify any issues with grinding, distribution or tamping. During the coffee extraction process,You can clearly see the flowing golden espresso extract, which helps you extract professional espresso. USEFUL TIPS: We recommend using fresh coffee beans or ground coffee. Please adjust the grinder setting to a finer setting or choose a finer ground coffee. It’s suggested to use 14 g(0.49 oz) ground coffee for a double espresso. Please use the WDT tool to break up clumps in ground coffee, reducing channeling and spurting during extraction. Please tamp the ground coffee evenly. Please remember to place the PUCK SCREEN. Please kindly note that if you use a bottomless portafilter, it may take several attempts to get a perfect shot PLEASE NOTE: Our portafilters are designed to fit snugly into the group head of CASABREWS CM5418 and 3700 Series, providing a tight seal when brewing. However, due to the varying tolerances between machines, some may fit more snugly than others. We suggest you confirm the position and the thickness of the ears on your portafilter before purchasing. The thickness of the ears: 4.4 mm