Shank Adapter, also called fiber optic coupler, is a small device that used to terminate or link the fiber optic cables or fiber optic connectors between two fiber optic lines. A fiber adapter allows fiber-optic cables to be attached to each other singly or in a large network, allowing many devices to communicate at once. Fiber adapters are widely used in light distribution frame, optical fiber communications equipment, measuring appliance and so on. Optical adapter comes in versions to connect single fibers together (simplex), two fibers together (duplex), or sometimes four fibers together (quad). Most fiber adapters are female on both ends, to connect two cables. Connecting two cables together can allow two devices to communicate from a distance through a direct connection with the fiber optic line. Some are male-female, which typically plug into a port on a piece of equipment. This then allows the port to accept a different connector than for which it was originally designed. We discourage this use because we find the adapter extending from the equipment is subject to being bumped and breaking. Also, if not properly routed, the weight of the cable and connector hanging from the adapter may cause some misalignment and a degraded signal. Fiber adapters are typically connecting cables with similar connectors (SC adapter to SC connector, LC adapter to LC Connector, etc.). Some adapters, called “hybrid”, accept different types of connectors (ST to SC, LC to SC, etc.). When attempting to connect two cables that are different shapes, it is necessary to use a hybrid connector. There are also adapters that can be used to attach a bare fiber-optic cable to a power adapter. This piece allows the cable to fit into a connection slot, whether into a mating sleeve or into an electronic device. The fiber-optic cable can be fit into an adapter that works with any of the standard shaped connectors. The fiber adapters are available with many types because of the diversity of the connectors. In order to realize the fluent fiber optic connection, the fiber optic adapter panel shapes or types should be in accordance with the fiber optic connectors or cables. Common shapes of the adapters are square, rectangular, or round that with FC, LC, ST, SC, MTRJ types. These simple types of adapters are often referred to as mating sleeves because they allow two cables to connect to one another. Some of these common line to line connectors are also built to connect three or four cables together. There are also single mode and multimode fiber adapters or single mode and multimode fiber optic connections. They are designed for singlemode or multimode cables. The singlemode adapters offer more precise alignment of the tips of the connectors. It is OK to use singlemode adapters to connect multimode cables, but you should not use multimode adapters to connect singlemode cables. Because this can cause misalignment of the small singlemode fibers and loss of signal strength.