Maxim Defense Industries CQB Stock, Gen 6, Standard Buffer, Collapsible, 4 Position, Fits AR-15, Black MXM-47502 Finally" a CQB stock built for comfort and durability for real-world use. No buttons to push" just pull the stock to deploy. At its most collapsed position" this CQB stock only adds 5.35" to your AR-15. At full extension" the Maxim CQB stock is the length of a standard extended M4 carbine stock. And with 4 total positions you can adjust for maximum comfort and multiple scenarios. Rapid deployment" purpose driven materials" and the functionality you need" the Maxim Defense CQB Stock is simply the most thought out" versatile" and durable CQB stock on the market. This stock assembly comes with a standard weight proprietary buffer" buffer spring and buffer tube. Not compatbile with standard AR-15 buffer tube assembly components.