A heavy flannel or molleton fabric is a dense and soft cotton fabric with great absorbency and high thermal insulation capacity. It is created when a roughenable yarn is used in the weft. Namely, then the fabric can be mechanically compressed to such an extent that the high-quality weave, in this case a double weave (commercially available would be the simpler plain weave), is hardly recognizable.

We specify the yarn count in Nm (number metric), the higher the number, the finer the yarn. A yarn count of Nm 100 means that 100 meters of a yarn weigh 1 gram. An additional digit is appended if the yarn is twisted from several single yarns, for example Nm 100/3 for a yarn made from three single yarns.