The SPEED Adjustable Nut Wrench is fully adjustable and extremely universal that can be used for the AEG buffer tube castle nut, and can also be used for the Madbull Daniel Defense MK18 and Lite series of barrel nuts. The SPEED Adjustable Nut Wrench uses harden drive pins and has a special machined ridge for better alignment on the nut. A special window opening allows visual of the drive pins for quick placement onto the nut.