M10 Blind Stopper. Stoppers can be used to close off any of the unused openings in the head plate. The M6, M10 and M12 sizes are fitted into the head plate from the inside, leaving a flat surface, while the M18, M27 and G3/4 are threaded into the ports from the outside.Like-for-like replacement parts for Applikon Biotechnology and Broadley-James brands of bioreactors.Applikon is a registered trademark of Applikon Biotechnology, Inc. Broadley-James and Broadley-James Corporation are registered trademarks of Broadley-James Corporation.