Astm A420ʻO ka kiko'ī maʻamau no ka piʻiʻana o ka piko o ka carbon a me nā kila eleele i hoʻohanaʻia no nā lawelawe haʻahaʻa haʻahaʻa. ʻO WPP6 ka mea nui i hoʻohanaʻia ma lalo o A420.
Ma waho aʻe o ka helu WPP6, e pili ana ka maʻamau o WPL9, WPL3, WPP8, WPL8, -135, -135,45,45,45,25,55,25,55,25,55,25,45,25,55,25,55