The Williams Ace in the Hole sight set is the perfect solution for mounting optics and retaining iron sights. The base features a picatinny rail for mounting scopes with an integrated peep sight in the rear. The rear peep will accept any of the standard Williams apertures. The set includes a Fire Sight front sight for excellent low light visibility. Aluminum construction. FeaturesPicatinny scope railRear 3/8" x .093" aperture has windage and elevation adjustmentInterchangeable apertures and ghost ring available separatelyCNC machined out of high grade aluminumIncludes steel fiber optic front sight