Corning called these creations "Glas-Snap" tumblers. The insert "snaps" in and out of the plastic holder. I really like the modern feel of this Freda Diamond design. Being made of Pyrex glass, they are good for hot or cold beverages.

This is how these Corning creations are described in the Corning archive: "Pyrex Mug with Black Holder. Colorless glass; black plastic; machine-made. Tapering cylindrical shape glass that sits in a black base with handle."

The 12 ounce size stands 5 1/2 inches tall when in the holder while the 8 ounce size stands 5 inches tall. There is a slight smoky gray color to the glass.

In the 1973 catalog which accompanied the recent Pyrex Centennial exhibit, these two sizes are shown in plastic bases of the following colors: Spring Blossom Green, Snowflake Blue, and Butterfly Gold. Sound familiar? Well it should if you are Pyrex collector. In fact, there was also a matching 1 Quart Serving Pitcher and a larger size 1 1/2 Quart Pitcher available to accompany these Glas-Snap mugs.

I am not yet sure what year the black plastic bases were produced but my guess is around the same time period. Excellent condition