*ADE RD3-023 Generation 2 Valkyrie is a 4 MOA GREEN dot designed to fit any pistol*The Valkyrie Gen 2 also fits name brand pistol manufacturer made Optics Ready pistols*ADE Valkyrie created a iron sight curve at the end of the bodyADE Does not know the screw spec every pistol manufacture used for their screw hole. Please ask the pistol manufacture what screw specs they used on the hole and ask them to provide the screw. If you can't get the screw to work properly, we recommend going to a local hardware store such as ACE Hardware to get the right size.