Truma Lagging pipe for a Combi camper trailer. Truma lagging pipe 75 mm is a special pipe used to guide and insulate the supply pipe under the vehicle. This is a useful solution when the supply pipe must be routed under the entrance door. This pipe can also be used as a supply pipe for the Trumatic E 4000/ C EH and Truma Combi heaters. The pipe has an external diameter of 75 mm and an internal diameter of 70 mm. It is flexible and covered with a waterproof plastic layer on the outside. The pipe is sold by the meter and is easy to install.