The most impotant element of connector is ferrule, strictly selected according to application. Single mode ferrules are characterized by high precision of production and centrality as well as precise execution of bore (diameter). They are supplied as pre-polished that mean that they are given preliminary radius what results in parameters of products.
Multi mode ferrules are also supplied as pre-polished with adjusted bore diameter to multimode cables. An adapter is a mechanical device used to aling and join two or more fibers with different connection type.