Texas Weapon Systems Basic Rear Peep Sight Gen-3 Use w/Top Cover Only Black. Non-adjustable. Graduated to 100 yard zero. Aperture diameter .070". For use with Gen-3 Top Cover ONLY. Specifications for Texas Weapon Systems Gen-3 Basic Rear Peep Sight for Gen-3 Top Cover: Manufacturer: Texas Weapon Systems Color: Black Fabric/Material: 6061-T6 Aluminum Weather Resistance: Yes Condition: New Country of Origin: USA Package Contents: Texas Weapon Systems Gen-3 Basic Rear Peep Sight for Gen-3 Top Cover Texas Weapon Systems 42317: Basic Rear Peep Sight Gen-3 Use w/Top Cover Only Black