Rear Sight Windage Adjustment SPRING (goes behind sight blade) fits GP100,New Model Blackhawk,Old Model Blackhawk,New Model Super Blackhawk,Old Model Super Blackhawk,New Model Single-Six,Old Model Single-Six,Old Army,Redhawk,Super Redhawk,Bisley Large Frame,Bisley Small Frame,Single Six Bisley (will work on some other sights too)
These are new from Ruger never installed (We are a Ruger parts dealer)