Maintain older Ethernet services across fiber spans that exceed the practical limits of copper. The StarTech SFP100BLHST is a 100BASE-LH SFP transceiver designed for 100 Mbps Ethernet over single-mode fiber at 1550 nm, giving network teams a direct path to extend legacy links without redesigning the surrounding environment. This module is built for infrastructure that still has value: remote buildings, distributed closets, industrial sites, and other locations where long optical runs are part of the network plan. Its MSA-compliant SFP design supports straightforward deployment in compatible ports, while the hot-swappable format helps reduce maintenance friction during upgrades or replacements. For teams balancing uptime and capital spend, the value is in precision. Rather than overbuilding for speed that the endpoint cannot use, this transceiver focuses on reach, compatibility, and predictable transport. It helps keep established 100 MbE services operational while deferring larger refresh cycles until they are truly warranted.