Pigtail SC/UPC SM 900UM G.657A 2M. Pigtail Extralink with SC/UPC connector is made on a  single-mode G.657A fiber, which is dedicated for FTTx technology. This fiber is characterized by  reduced bending radius, without increasing attenuation. This is a very important feature during the construction of FTTx networks due to the large number of changes of optical line direction and because of the small size of cabinets and distribution boxes. Pigtail is used mainly in client cable terminations in the customer's sockets and in end switchgear.