Ko ngā peera roera whakapā koki SGL te mea pai ake mēnā e hiahiatia ana he tika me te pakari teitei, me te kaha kawe kawenga nui. Ka tutuki te tino tika mā te whakamahi i ngā mowhiti peera tika, mīhini, whakapakeke me te whenua me te kōtaha tapatoru. Ka whakaritea he huihuinga roera me te whare herehere mai i te kirihou ātete-kakahu i waenganui i ngā mowhiti peera. Mā te whakamahinga o ngā huānga hurihuri tapawhā (he rite te diameter ki te roa) ka tino whakapai ake i ngā āhuatanga kinematic o te peera. He tino ōrite te oma o te peera me te iti o te waku, ā, he pai mō ngā tere teitei.
