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 white cover and trough now sold as an assembly along with the primer slider primer lever 6-32 x 1/4 screw and o-ring. This assembly replaces Lee parts: LM3252 LM3247A LM3247B and LM3251