The Wheeler Engineering Delta Series Vise Block is an innovative and versatile tool that is designed for compatibility with almost any AR-15, AR-10 or LR-308 upper receiver. The Delta Series AR Upper Pic Rail Vise Block will secure AR-15 uppers by engaging the takedown lugs on the bottom of the receiver. By reversing the direction it will secure most AR-10 style uppers in the same manner. In addition it will secure any pic rail on a hi-rise, standard flat top or many other integrated rail guns by sliding onto and clamping the rail. The durable machined aluminum construction and precise tolerances ensure a secure hold essential for removal and installation of stubborn barrel nuts as well as a variety of other tasks. The multi-function design holds AR-15 and AR-10 uppers and can secure any Pic-Rail receiver by clamping the rail.Notes:For use with a securely mounted, 6" or larger bench vise (sold separately) The block's Picatinny rail dovetail clamp is a precision surface. Care mu...