The Sierra K is a purpose-driven compact stock, optimized for use on PDW and compact weapon systems. Features include reduced overall size and slim cheek profile, snag-free adjustment lever, limited rotation QD and integral fixed sling mounts, internal tensioners, and anti-slip buttpad. Mounts via shortened compact Mil-Spec receiver extension (sold separately). FeaturesOptimized for PDW and Compact Weapon SystemsLow-Profile Adjustment LatchSlim-Profile Ergonomic Cheek WeldColor-Matched Steel HardwareAmbidextrous Fixed Sling Mounts and Limited Rotation QD MountsMil-Spec Materials and FinishesMounts via Sierra K Receiver Extension Kit (not included) Note: Installing on a standard length MIL-Spec Buffer Tube will not allow the stock to fully collapse