oh god! this is what i hate about this country, when will you people move to the normal system, the metric system. its like this. there are 10mm in a centimeter. hence the "milli" prefix, DUH! so 45 mm is 4.5 cm. ~2.5cm is an inch. so that makes 45mm to be close to like 2 and 3/4 inch thick or in NORMAL numbers 1.8 inch thick. also, how hard is it to go here http://www.fatmat.com/fatmat/bulk/100ft.htm and see for yourself that it says that its 45mm on the manufacturer site. damnit, what do you people do in school, eat paintchips? i need to move to japan