Vapor barrier films(RH-group) protect the insulation from moisture falling from the inside (steam from accommodations). They consist of two layers with reinforcing net between them.
Wind- and moisture-protective diffusion membranes(FM-, FS-group) protect the insulation from moisture from the outside (under roof or facade) and remove moisture from the insulation. They consist of one non-woven layer, smooth on the outside and hairy on the inside.
Superdiffusion membranes(RS-group) belong to the new generation of films. They consist of three layers joined by ultrasonic sealing. The inner layer is the nano-product which not only provides one-sided steam conductivity, but also removes moisture from the insulation.