Ko te āhuatanga tino nui ko ki te pupuri i te elasticity caster polyurethane tiketike i roto i te whānuitanga o te pakeke, me etahi aunoa kaha pai, te hinu resistance me te pekerangi ātete, āhuatanga pāmahana iti pai.

Polyurethane caster taua rahi kaha kawenga o 6 ki te 7 nga wa te potae rapa e taea te whakatutuki i te tukanga ahumahi tonu me te aunoatanga, hua i roto i te hanga, me te whakamahi i iti rawa ururua, a nui atu, te wahi ururua tupare tinana ka taea te hangarua hoki i ētahi atu hua polyurethane, e kore e meinga poke taiao, me te he kuware tona tukanga ahumahi-- wai makanga niao, e maka ana wira ko te momo hou kahore aho, i mohiotia ko rite te rautau 21 potae matomato, wira polyurethane, ka hei te heke mai whanaketanga o te mauiui auraki, kua he opuaraa tono whanui te ahumahi mauiui.