Fiber optic adaptors form a small, but critical, part of the hardware used in an optical-fiber cabling system. While the importance of fiber adaptors is often overshadowed by connectors, product manufacturers continue to stress the significant role that these devices play in overall interconnection performance. Available for more than a decade, the fiber adaptor has been a relatively stable device, with no really revolutionary breakthroughs in its technology. Rather, cable installers have seen incremental and evolutionary product enhancements, such as the introduction of a variety of metal, polymer, and ceramic materials for the adaptor sleeve, and the introduction of hybrid adaptors. During all this time, the fiber optic adaptor’s function has remained the same, which is to join and align two connectors. Fiber Adaptors are available to join connectors such as SC-to-SC, ST-to-ST, FC-to-FC, and different styles of connectors. The latter devices are called hybrid adaptors and are used, for instance, to join ST and SC connectors. As we all known, hybrid adaptors offer a solution for hybrid applications where the two different kinds of optical connectors or cable assemblies need to be linked with each other. SC to ST hybrid adaptors are with plastic housing, flange type, zirconia sleeve for single mode and broze sleeve for multimode. Blue for single mode PC and beige for multimode PC. FC to ST hybrid adaptors are also flange type with plastic housing. Blue for single mode PC and beige for multimode PC. SC to FC hybrid adaptors are available with plastic housing and metal housing. Plastic body adaptors are flange type while metal adaptors are square type. With many types of fiber optic connectors having been developed over the last decade, cabling installers have expressed concern about the inability of fiber adaptors and connectors from different vendors to interconnect. That is not a problem any longer, because specifications for intermateability have been issued by by the International Electrotechnical Commission. Today, most product manufacturers follow these specifications.