Made of aluminum, this dose ring is strong and . (for 51mm handle) Aluminum material not rust. Thanks to the small magnets, the dosage ring does not slip and ensures a particularly stable fixation. Our filters 51mm are made of multi-layer sintered stainless steel 316L. Compared to 304 stainless steel, 316L is more sustainable at high temperatures. With our dosing ring, it significantly reduces the annoying scattering of coffee grounds when grinding directly into the handle. Especially helpful for electrostatic powder. Our 150μm disc filter can enhance the coffee aroma more effectively than other 50μm disc filters while ensuring the filtering effect, and is more suitable for espresso machines. The coffee dose ring can be wiped quickly with a brush, sponge, etc. or simply wiped with a damp cloth. The 150 Micrometre Puck filter simply rinses under running water to remove any dirt inside. Eco-friendly, and reusable. Note: Not dishwasher safe. Filling funnel fits most 51mm filters. NOTE: It is not compatible with some coffee makers. Compatible with Portafilter , Bezzera BZ10. Please measure the inside diameter of your handle and dosing ring before purchasing. It is perfect for coffee machines and suitable for grinding coffee in cafes, bars, restaurants and more. Small size, light weight, exquisite workmanship. Easy to carry.