FEER B5 SIERRA K PATENT# US 11644272 Field Expedient Elevated Riser B5 SIERRA K Compatible WITH B5 SIERRA K Carbine Stocks For touchpoint based shooting, allows user to maintain positive cheek weld with various height options available. Elevated, tool-free buttstock riser Maintains positive cheek weld when running elevated optic mounts Perfect addition to your carry handle build Multiple height options available  Adds .75” elevation over buttstock For use with holographic, red dot optics and scopes Full charging handle pull with stock collapsed and FEER mounted  Made in USA from high strength 300°+ heat and solvent resistant nylon 12