Tshwj tsis yog tsis muaj lwm daim ntawv qhia, e-iav fiberglass sib xyaw ua ke rau cov vaj huam sib luag pob tshab yuav tsum muab cia rau hauv qhov chaw qhuav, txias thiab noo noo thiab noo noo. Qhov zoo tshaj plaws siv nyob rau hauv 12 lub hlis tom qab hnub ntau lawm. Lawv yuav tsum nyob twj ywm hauv lawv thawj lub ntim kom txog thaum tsuas yog siv ua ntej siv. Cov khoom tsim nyog rau kev xa khoom los ntawm txoj kev ntawm nkoj, tsheb ciav hlau, lossis tsheb thauj khoom.