Schaerer WMF Descaling Liquid 2 x 750 ml Bottle

I have been using this product since 2003 in my DeLonghi Super Automatic coffee machines. I wore out my first machine after 15 years use and checked for scale buildup in it before I bought a new machine. It was very clean inside the boiler and the hoses. The mechanical parts of the old machine had worn out and no longer available. I have been using it in my current machine since 2018 and no problems related to scale buildup and we have very hard water here.