Optic adapters are necessary for conection between pigtails and cords. Fiber-optic adapters are intended for installation in the optic patch-panels and optic boxes. If you use optic adapters, it allows to make your resolution more universal. Of course, you can weld optic patch-cords and pigtails to the feber and directly pull out from the box without optic adapters using, but if you use them, you will not be able to connect to any connector. Also if you use optic adapters you will nullify all effects on the welding location and other components in the patch-panel. Optic adapters are not divided into single-mode and multimode types, they are universal. On this page you can find classic adapters, which have the same type of connectors, and hybrid - with different types of connectors.