Ikhoyili ye-air core yakhiwe izingxenye ezimbili, okuyi-air core kanye nekhoyili.Uma sibona igama, ngokwemvelo kufanele kuqondwe ukuthi akukho lutho phakathi nendawo.Amakhoyili ayizintambo eziyindilinga eyinxeba ngendilinga, futhi izintambo zivaleleke komunye nomunye.