Moralo oa sejoale-joale: Karolo e ka hare ke khetla ea tšepe, 'me mocheng o kantle ke khetla ea mokokotlo oa khalase e matlafatsang (FRP) Shell. Ho na le lekhalo la 0,1mm ~ 3.5mm pakeng tsa likarolo tse ka hare le tse kantle. Le ha khetla ea ka hare Shellks, lintho tse kotsi li tla phalla feela lekhalo 'me li ke ke tsa koata kapele ho silafatsa tikoloho.