This Play-dough mini extruder pen is now available at Costco. I know it works for PMC because I have two mini-extruders in my teaching supplies bins. They used to be sold as keychains. One I bought mail order from Linda Kaye-Moses. The other, Toys R Us, I suppose?
I haven’t seen them for sale in a while, so I wanted to give you the heads up that you can find them now! Oil the inside just a bit when using with metal clay.