When it comes to tritium gun sights, aluminum sleeves and painted-on white rings are the norm. Night Fision breaks the mold, literally. Their patented, injection molded sleeve design not only holds the tritium vials securely in place, it creates a brighter and more durable ring, they call The Perfect Dot, that provides maximum visibility both day and night.Features :"Optics Ready Stealth Series Night Sight Set with 0.315" Serrated Front and 0.302" Serrated Square Rear"Yellow Front Ring with Domed Lens and Green Tritium and Blank RearDesigned for Sig Sauer P-Series