Just purchased a used Selexx CNC. The 5 x 12 vacuum table isn't operating, my plan is to get it back up and running. Some of the holes have neoprene plugs, many are deteriorating. I'd like to replace these. Not sure if they were something put in by a previous owner, or if it's a common part. Any ideas on where to find them 1.125" x .5" with assertional "nipple" photo below for reference.