A i-cylindrical gearisethi, evame ukubizwa ngokuthi “amagiya,” inamagiya ayisilinda amabili noma ngaphezulu anamazinyo ahlanganayo ukuze adlulise ukunyakaza namandla phakathi kwamashafu ajikelezayo. Lawa magiya ayizinto ezibalulekile ezinhlelweni ezehlukene zemishini, okuhlanganisa ama-gearbox, ama-transmissions ezimoto, imishini yezimboni, nokunye.
Amasethi amagiya angama-cylindrical ayizingxenye ezihlukahlukene futhi ezibalulekile ezinhlobonhlobo zezinhlelo zemishini, ezihlinzeka ngokudluliswa kwamandla okuphumelelayo nokulawula ukunyakaza ezinhlelweni eziningi.