Strike Industries drop-in replacement stock for AR/15/M16 carbine using mil-spec sized receiver extension tubes. The Viper stock integrates features sought by military professionals and firearms enthusiasts around the world. Strike Industries came up with a lighter, compact stock, at an even more attractive price point.FeaturesSlide on replacement for factory collapsible butt stockQD sling mounting points integrated on both sides in positions for optimum usageEnhanced cheek weldEasy to replace and quick to installDesigned for use with and without rubber buttpadLength of pull (LOP): 11.25a ^2 to 14.25a ^2