Each pack contains one 40″ piece of 0.040″ diameter Ultra Super Flex fiber in brilliant blue. USF fiber is our standard bright fiber, which is excellent for general use in a variety of aiming applications. USF flares easily with heat (if needed), allowing for installation in nearly all sights styles.
Please note: Blue fibers rely on UV light to produce maximum brightness. This can be achieved by using the fiber outdoors, even in overcast conditions. Additionally, a UV sight light may also be used. Blue fibers may appear dull indoors where UV light is minimal.
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