There was a third generation design change on Lee's primer feeder effective October 27 2011 eliminating nuisance damage to the primer sliders and trough cover during operation. Formerly the gray cover and trough now sold as an assembly along with the primer slider primer lever 6-32 x 1/4 screw and o-ring. These parts are no longer available individually. This assembly replaces Lee's parts: LM3254 LM3253A LM3253B and LM3251