1) He nui ka laulā o ka ʻāpana, a he mea kupaianaha ka hopena o ka piholo ʻana o ka puʻu.
2) Nui ka modulus ʻāpana.
3) ʻO ka manawa kiʻekiʻe o ka inertia e hoʻonui i ka paʻakikī o ka paia paila pepa kila a hoʻemi i ka deformation kūkulu.
4) Ka hopena anti-corrosion maikaʻi loa.
5) He maʻalahi ke kūkulu ʻana a ua pōkole ka manawa kūkulu.
6) ʻO ka hoʻohana ʻana i nā mea paila pepa kila hiki ke hoʻomaʻalahi i ka paʻakikī o nā mea nānā a me nā mea ʻōnaehana.
7) Loaʻa koke: Hana ʻia nā puʻu pepa i hana ʻia i ke anu ma nā nui he nui ma mua o nā puʻu pepa i ʻōwili wela ʻia, e hoʻonui ana i ka helu o nā lā ʻōwili e koho ai. ʻO ka manawa hana maʻamau he 2 pule
8) Kūʻai kūpono: ʻOi aku ka liʻiliʻi o ke kumukūʻai o ka hana ʻana i ka puʻu pepa i hana ʻia i ke anu ma kahi o 30-40% ma mua o ka puʻu pepa i ʻōwili wela ʻia
9) ʻOi aku ka liʻiliʻi o ke kumukūʻai e lawe ai: Ma muli o ka nui o nā mea hana paila pepa i hana anu ʻia, ʻoi aku ka nui o ka manawa e loaʻa ai kahi wili ma kahi kokoke ma mua o ke kūʻai ʻana i nā paila pepa i ʻōwili wela ʻia. Eia kekahi, ʻo ke koho nui o nā paila pepa i hana anu ʻia e hiki ai iā ʻoe ke loaʻa nā ʻāpana me kahi modulus ʻāpana kokoke i kāu mau kikoʻī hoʻolālā me ka ʻole o ka hoʻonui nui ʻana o ke kaumaha.
10) ʻOi aku ka maʻalahi o ke kau ʻana: ʻAe nā laka pepa i hana anu ʻia no ka hoʻohuli ʻana he 25-degere, ma mua o ka hoʻohuli ʻana he 7-a-10-degere i ʻae ʻia me ka puʻu pepa i ʻōwili wela ʻia me ka hoʻohana ʻana i nā laka pōpō-a-socket