Spliced bare Optic Fibers are susceptible to breakage . Using the Single Fiber Protection Sleeve TK-15 protects the fiber from stress and breakage . Fiber protection sleeves are provided in 60mm or 40mm length. Fiber protection sleeves offered have a heat shrinkable outer coating made of polyethylene , built in stainless steel rod for rigidity. using a fiber protection sleeve after the fusion splicing protects bare fiber joint from dust, humidity - providing strength & protection to the fiber joint. Fiber protection sleeves are offered in packs of 50 and 100.