Product Description Maxim Defense CQB Carbine K AR9 Roller Delayed Blowback Buffer Tube Kit - Carbine Maxim Defense CQB Carbine K AR9 Roller Delayed Blowback Buffer Tube Kit - Carbine at Primary Arms Browse all Primary Arms deals $209.66 Out of Stock Price checked 6 days ago Buy Now at Primary Arms Secure checkout Easy returns or compare prices Amazon eBay Product Details Brand Maxim Defense Maxim Defense