We designed our grater card to have a long grinding area right down the middle. This means the grinder actually works instead of being extremely fiddly. Other brands usually have a picture or shape in the grinding area making it pretty much useless.
It is 85mm by 50mm and 1mm thick with a grinding area of 60mm by 25mm.
The grater card works especially well in conjunction with our Rolling X. You simply place your paper in as usual then hold the card over the top while you can grind directly into the paper. Extremely convenient as a travel kit to avoid picking your herbs by hand.