Peep sights can be adjusted for windage and elevation in order to get them aligned with your front sight and shooting on target. Windage is adjusted with the side screw and elevation with the top screw. Once the screws are loose, you can move the sight up or down to adjust it to your liking. Be sure to tighten the screws back up once you're done adjusting the sight and add a little blue loctite to hold them in place.