Aia ka pahu pahu cylinder ma waena o ke poʻo cylinder a me ke kino cylinder, i ʻike ʻia ʻo ka moena cylinder.ʻO kāna hana ka hoʻopiha ʻana i nā pores microscopic ma waena o ka pahu cylinder a me ke poʻo cylinder, e hōʻoia i kahi sila maikaʻi ma ka ʻili i hui ʻia, a laila e hōʻoia i ka sila o ke keʻena puhi ahi e pale i ka leakage cylinder a me ka wai.