External components, connector shells and inserts are often metal and can be aluminum, stainless steel, brass, titanium, or even composite to meet the demanding harsh environment conditions. Selection of a ferrule material should not be based on cost alone, but on a combination of relevant performance factors that include durability of ferrule materials, connector mating frequency, and ability of each material to retain endface geometry and surface finish over time. Material Properties. Fiber optic joints or terminations - where cables are terminated - are made two ways: 1) connectors that mate two fibers to create a temporary joint and/or connect the fiber to a piece of network gear (left) or 2) splices which create a permanent joint between the two fibers (right). Either. A fiber fast connector, also known as a mechanical splice or cold connector, is a field-installable connector that terminates fiber optic cables without requiring a fusion splicer. To meet these varied requirements across different applications, connector manufacturers must use many different materials. An adapter is a mechanical device us ed to align and join two or more fibers with different connection.