Ana amfani da bututu na musamman na man fetur don hakar rijiyoyin mai da iskar gas da jigilar mai da iskar gas.Ya hada da bututun hako mai, da rumbun man fetur, da bututun tsotsa.Maibututuana amfani da shi ne don haɗa ƙwanƙwalwar ƙwanƙwasa da ƙwanƙwasa da kuma watsa ikon hakowa.Ana amfani da rumbun man fetur ne don tallafa wa bangon rijiyar burtsatse a lokacin hakowa da kuma bayan haka don tabbatar da yadda rijiyar mai baki daya ke aiki yadda ya kamata a lokacin haka da bayan haka.Bututun tsotsa ya fi jigilar mai da iskar gas daga kasan rijiyar zuwa saman.

Rukunin mai shine hanyar rayuwa don kula da aikin rijiyar mai.Saboda yanayin yanayin yanayi daban-daban da kuma yanayin mawuyacin halin da ake ciki na ƙasan ƙasa, haɗin haɗin gwiwar daɗaɗɗa, matsawa da damuwa na torsional akan jikin bututu ya gabatar da buƙatu mafi girma don ingancin casing kanta.Da zarar kwandon kanta ya lalace saboda wasu dalilai, zai iya haifar da raguwar samar da rijiyar gabaɗaya ko ma guntuwa.

Dangane da ƙarfin ƙarfe da kansa, ana iya raba casing zuwa nau'ikan ƙarfe daban-daban, wato J55, K55.N80, L80, C90, T95, P110, Q125.V150 da sauransu.Yanayin rijiyoyi daban-daban da zurfin su kuma suna amfani da ma'aunin ƙarfe daban-daban.A cikin yanayi mai lalata, ana buƙatar kashin kanta don samun juriya na lalata.Inda yanayin yanayin ƙasa ke da sarƙaƙƙiya, ana kuma buƙatar casing don samun aikin hana rugujewa.