I believe the higher end Dr. Grabow's, like the Royalton bulldog, have acrylic stems. Other kinds of plastic
stems tend to chew through, but softie stems solve that problem. The one MM cob I maintain for smoking
with its filter, I fit with a softie. I'm glad to know about the retrofit Grabow stems. Unless you are on a really
tight budget, it would be worth the ten bucks, without a doubt. P.S. My other MM cobs have Forever stems,
hence don't use filters.