Heater Hose / Blower Hose Cardboard

Heater hose / blower hose engine bay.
Hose between the blower box and the heat exchangers.
Heater / air filter hose made of cardboard.
Dimensions: 50 mm x 1080 mm.
Type 1 engines - from 1/63 onwards.

At several places in the car there are tubes for heating and ventilation.

It is a PAP hose (paper/aluminum/paper), as Volkswagen originally used. Thanks to the inner and outer paper wrapping, the warm air is retained longer (insulated). With aluminum only, the warm air would escape outside the tube. Since the entire heating system is based on warm air and has to travel a long way, heat losses must be minimized.