E whā ngā wāhanga e hono tahi ana ngā peera roera whakarara: te koeko (mowhiti o roto), te kapu (mowhiti o waho), ngā roera whakarara (ngā wāhanga hurihuri) me te whare pupuri roera. Ka whakamahia e ngā peera roera whakarara koki-waenga me te koki-paripari raupapa ine te waehere koki whakapā "C" me te "D" rānei i muri i te tau poka, engari kāore he waehere e whakamahia ana me ngā peera koki-noa. Ko ngā peera roera whakarara koki-waenga te nuinga o te wā e whakamahia ana mō ngā rakau pinion o ngā taputapu rerekē i roto i ngā motuka.
