Buyers must prioritize fiber type (Single-mode G.652.D or Multi-mode OM3/OM4/OM5) based on transmission distance. For long-haul telecommunications, Single-mode is essential, while OM4/OM5 is preferred for high-speed data centers. Key performance metrics include insertion loss (typically <0.3dB) and return loss (>50dB for PC, >60dB for APC connectors). Additionally, ensure the jacket material meets safety standards like LSZH (Low Smoke Zero Halogen) for indoor use or PE with anti-UV protection for outdoor aerial or duct installations.