The Armanov Quick Disconnect replaces original Dillon Powder Measure half-ring retention. Just remove original half-ring retention and install Armanov Quick Disconnect for Dillon. It has two internal springs and allows quick change of powder bar from one toolhead to another. Armanov Quick Disconnect fits on the RL550, XL650, XL-750, and Super-1050 powder measures. It is specially useful In combination with Clickable Armanov powder knob. So you can your reuse powder measure on additional tool heads and adjust powder quantity with a simple click. This allows for quick and tool-less removal and installation of Dillon Powder Measures.