[Automatic Calibration Powder Tamper] This espresso coffee tamper has 2 interacting constant force springs and a stopper which can automatic spring back and can keep the pressure at 30 lb all the time. ;) [With Scale Design] This coffee press has precise scale design and you can precisely adjust and control whether the pressing of the coffee powder is in place. ;) [Food Grade 304 Stainless Steel] This coffee press tamper is made of food grade 304 stainless steel material which is rust-proof and very sturdy safe to use daily. ;) [3 Sizes Optional] There are 3 different sizes to choose 5199mm 5399mm 5899mm. It is suitable for various types of espresso portafilter baskets. (Note: Please make sure your portafilter size before purchasing.) ;) [Widely Uses] An espresso tamper is a great addition for coffee or espresso lovers. It is perfect for home office cafe bar etc a great gift for any coffee fans and families. ;)