Mwanjira zambiri mawaya amkati a zida zamagetsi ndi zamagetsi, pomwe amakumana ndi mafuta pa kutentha kosapitilira 60°C kapena 80°C.Uniform insulation makulidwe a waya kuonetsetsa kuvula ndi kudula kosavuta.Kugonjetsedwa ndi zidulo, alkalis, mafuta, chinyezi ndi bowa.