Li-valve tsa serurubele tse tsamaeang ka botlalo, tse nang le ts'ebetso e ntle ea ho thibela ho bola, ho ea ka pono ea meralo, ho na le li-halves tse peli le mofuta o le mong 'marakeng, hangata li entsoe ka thepa ea PTFE, le PFA, e ka sebelisoang mecheng ea litaba e senyang haholoanyane, bophelo bo bolelele ba tshebeletso.