Valavu imalumikizidwa ndi zingwe ziwiri, ndipo kapangidwe kake ndi kolimba.Chifukwa cha kutsekeka kwakufupi kotseka ndi kutsegula kwachikasu kwa kasupe, liwiro lotseka ndilofulumira, lomwe lingathe kuchepetsa kwambiri zochitika za nyundo zamadzi.Valve ili ndi mawonekedwe a voliyumu yaying'ono, kulemera kopepuka, kuchitapo kanthu tcheru, kusindikiza kodalirika, kukhazikitsa kosavuta, ndi zina zotero. Ikhoza kukhazikitsidwa molunjika kapena molunjika.