For applications where access and protection are both critical, self-wrapping fiber optic cable protection sleeves provide an alternative to heat shrink that's worth considering. But, that's not always the best option. Heat shrink tubing offers a clean, semi-permanent way to seal and protect cable assemblies. It's widely used in electrical installations, but it comes with. In modern FTTx and PON networks, fiber optic splice closures are the enclosures that protect fiber splice points from moisture, dust, and physical stress. Looking at your measurements you average less than a dB of attenuation on each.