I want to create a filter with 3 sliders: diameter, height and strength like on this page: https://www.supermagnete.de/eng/disc-magnets-neodymium
I have these values stored as attributes of products but they are all in the form of text, for example the string "20 mm", not a number. I am willing to put some manual work into transferring this data to a numerical form if necessary.
What is the easiest way to do this?
Note that there are plugins which can do it for the price but I am not sure about custom attributes.