18B301 up for sale is a vintage blender threaded bakelite cap and also the stainless blade insert, this came from a vintage blender we just dont know exact brand waring or hamilton beach or other brand , dimensions are givin to help you figure out this will fit your unit, the stainless cap has a outer diameter 2 1/2 x 1 3/4 tall , the bakelite part is just over 2 5/8 on the smallest area of the thread then it is 1 1/4 tall the outer diameter over the three lugs is about 3 1/4 inch, missing rubber gasket but the cap and cutter look good the cutter spins free and clean , nice parts for your old blender , these come as shown in the photos ,