Zoben fistan yana da daraja kuma ba zoben madauwari ba ne a cikin jihar kyauta. Girmansa na waje ya fi diamita na ciki na Silinda girma. Saboda haka, bayan an shigar da shi a cikin silinda tare da piston, yana haifar da ƙarfi na roba kuma yana manne da bangon Silinda.

Ana matse zoben piston a ƙasan ƙarshen ragi na zoben a ƙarƙashin aikin matsin iskar gas, don haka iskar gas ɗin ke gudana zuwa bayan zoben kuma yana faɗaɗa, kuma matsa lambansa ya faɗi. A lokaci guda, ƙarfin ƙarfin iskar gas a kan zoben baya yana sa zoben piston ya fi dacewa da bangon Silinda. Lokacin da iskar gas ɗin da aka saukar da matsin lamba ya yoyo daga tsinkayar zoben iskar gas na farko zuwa saman jirgin sama na zoben iskar gas na biyu, ana matse zoben gas ɗin a ƙasan ƙarshen ƙarshen ramin zobe na biyu. Yana zagawa zuwa bayan zoben kuma ya sake faɗaɗa, kuma matsa lamba yana ƙara raguwa.

Idan aka ci gaba da wannan, matsa lamba da kwararar iskar iskar gas daga zoben iskar gas na ƙarshe sun ragu sosai, don haka adadin iskar gas ɗin kaɗan ne. Saboda haka, na'urar rufewa ta "labyrinth" da ta ƙunshi ƴan zoben iskar gas tare da yanke ƙulle-ƙulle ya wadatar sosai don rufe babban matsi mai ƙarfi a cikin silinda.