ʻO ka ʻōpala ʻōpala Butyl kahi ʻōpala kiʻekiʻe me ka pale wela kiʻekiʻe. He haʻahaʻa haʻahaʻa haʻahaʻa a me ka moisture permeability. Hoʻohana ʻia ʻo Butyl rubber sheet i nā noi ʻē aʻe he nui, ʻaʻole hiki ke loaʻa i nā kinoea, ozone, kukui ultra violet, kemika a me ka weath-ering.
