Question: what are sig xray sights?
Answer: Sig Sauer's New X-RAY Tritium Sights. I don't normally think of sights as “optics” per-se, but Sig Sauer's Electro-Optics division is rolling out their new X-RAY pistol sights. They're a 3-dot tritium system, but these tritium inserts maintain a clean white color in daylight.