Ko te paera taki, e mohiotia ana ko te paera kore-whakahoki, ko te waapa kotahi-ara ranei, he taputapu miihini i hangaia hei tuku i te wai (wai, hau ranei) kia rere ki te huarahi kotahi anake i te aukati i te rere whakamuri (whakamuri) i roto i te punaha. Ka mahi i runga i te pehanga o te wai i roto i te punaha. Ka rere te wai ki te huarahi e tika ana, ka pana atu ki tetahi waahanga neke, penei i te kopae, te poi, te diaphragm ranei, i roto i te piha. Ko tenei mahi ka whakatuwhera i te paera, ka taea te rere o te wai. Mena ka ngana te wai ki te rere ki te huarahi whakamuri, ka heke te pehanga, ka kati te waahanga neke ka hiritia te ara rere. Ko tenei tikanga ka mahia e te wai ake, ka whakakore i te hiahia mo te puna hiko o waho.
Rahi: DN80-300
Pēhanga: PN10-16, Class150
Rauemi: rino whakarewa ,CF8/304, parahi