d1 is d2 (default 1) coffee measuring cup(s), standard d3 (default: 1 volume unit=1 cup of drinkable coffee), d4 subunits.
Coffee measure is a unit of volume that is not, strictly speaking, is a unit of measurement , but rather a name for a measuring cup with slightly different size, but usually 15 to 20 ml. The measure is designed to measure the adequacy 1-1.25 cups drinkable coffee .