HiViz ARN21 Folding AR Back Up Sight Black Folding for AR-15
https://www.tandktactical.com/shop/613485590449-hiviz-arn21-folding-ar-back-up-sight-black-folding-for-ar-15-39638
https://www.tandktactical.com/web/image/product.template/39638/image_1920?unique=ccdbc16
Folding back up sight for AR-15.
