When we say that a paper towel is very thick or thin, we can't say how thick it is, because it's difficult to accurately describe it by hand feeling alone. In the paper industry, we usually use gram weight to describe. For example, when a piece of paper weighs 50 grams, it means that the paper weighs 50 grams per square meter, which is commonly referred to as GSM. By comparing the GSM of different papers, we can know the thickness of the paper. The toilet roll paper used in the toilet is 20gsm for single layer, 15gsm for double layer, and 13.5gsm for three layers. Paper towel is 40gsm for single ply and 19-20gsm for 2 layers and 13.5gsm for a 3 layer.