This one optical fiber adapters are used in connecting fiber optic connectors, it is called Hybrid fiber optic adapter when the opposite connectors are different. Features: High size precision Good interchangeability, Good duplication, Good resistance to wear, Good temperature characteristic.  Applications: Optical fiber communications system, Optical instruments measuring appliance, Optical fiber CATV, Optical fiber sensor. Specification: Insertion Loss: PC/SM: below 0.2dB PC/MM: below 0.3dB PC/UPC: below 0.15dB PC/APC: below 0.2dB Return Loss: PC:  above 50dB  APC: above 65dB Exchangeability:   below 0.1dB Tensile strength:   above 100N Durability: 1000times Operating temperature: 45 to 80 degree Celsius. AVAILABILITY: Simplex/Duplex adaptor available Different mateiral available SM/MM available Various type