Good quality with operating instructions. Necessary to slow down the calcification process of the coffee machine. The filter can be used without difficulty. Should start Before you completely hold under water to the existing air to remove it completely, it sucks then completely full of water. He should change every two months under normal use, during heavy use simultaneously with the decalcification of the machine. A setting for water hardness is also available. The price compared to other providers, it is on Amazon perfectly fine !! Even in the low 5 pack available. For good coffee experience highly recommended.