Vtg. 8 Plastic Drinking Glasses-Has An Inner Glass. 4 Different Colors

Description

Vintage 8 Plastic Drinking Glasses-A Glass Within A Glass.  New and Unused. Made in USA by Falcraft.
They belonged to my Grandmother. The box fell apart.  I'm guessing they are from the 1950s?
Part of the box says.... Dishwasher Safe, Unbreakable in Normal Use. Keeps Hot Drinks Hot and Cold Drinks Cold.
There are 8 outer plastic glasses. 2 Blue, 2 Pink, 2 Yellow and 2 Green. The outer glasses have a etched pattern on the outside of the glass. (see 3rd photo)
There are 8 other plastic glasses that go inside the outer plastic glass.  2 Blue, 2 Pink, 2 Yellow and 2 Green. The inner glasses are smooth on the outside. (see 3rd photo).
You can put the same color inner glass inside the same color outer glass, or switch them around for a different look.
The outer glass is 5 inches tall and measures 2 3/4 inches across the top of the glass.  When the inner glass is in the outer glass, they are 5 3/4 inches tall.
They were all in a large box. Some of the inner plastic glasses have a few marks from them rubbing against the other glasses. See last photos.