Refractory fibre is generally divided into paper and blanket. There is a distinction between the two relating to binders and thickness.
Papers are those which have binders to keep the pressed fibres in a sheet or roll. These binders burn off during the firing process
Blanket does not have binders and is much thicker.
These two forms of refractory fibre generally exhibit a difference in thickness.
Papers range from cartridge paper thickness, to around 6mm thick.
Blanket tends to be 25mm and thicker, although there is some 12mm I understand.