Wasu nau'ikan konewa suna rage iskar oxygen, yayin da wasu ba sa.
Konewa yana da ƙarfi, zafi-saki oxidation-raguwa dauki, wajabta abubuwa uku: oxidant, mai raguwa, da zafin jiki wanda ke kaiwa bakin kofa.
Yayin da oxygen shine sanannen oxidizer, ba shine kadai wakili ke iya wannan rawar ba. Misali, a cikin konewar hydrogen, Ana amfani da iskar hydrogen da chlorine maimakon oxygen.