Attach a push button sling to your M4 and carbine stocks without integral bases with the GrovTec Sling Tail Buttstock Push Button Base Adapter. Featuring a steel keeper that acts like a catch lock, this easy-to-use adapter creates a strong and secure base to anchor your push button slings onto a carbine stock without integral bases. Designed to fit multiple styles of rifle stocks with sling slots. Comes with an optional rubber O-Ring for quiet use and to keep the catch lock securely in place. Sling attachment for M4 and carbine stocks without integral bases Strong, secure base for push button slings on carbine stocks without integral bases Fits multiple styles of rifle stocks with sling slots Steel keeper acts like a catch lock Includes optional rubber O-Ring