Thermoduct is a new product from Webasto in conjunction with 3M. It is a heating insulation system for warm air ducted heaters. It can improve the heat output of your heater up to  25%. Thermoduct is available in ¾ meter length in ducting size of 60mm, 80mm,100mm and 150mm. It is very quick and easy to fit. Simply slide over the top the ducting. For boats with existing ducting that is not very accessible there is rap around length available which is very easy to just wrap around your ducting and cable tie on.