Material - Acrylic fabric on foam
They do NOT have a base

Images are printed onto a foam base, with a Velcro strip that is used to close the stubby holder

The image is transferred to the stubby holder via a dye sublimation process
They can be washed, but care needs to be taken in doing so. Wash gently in cold water
Further examples can be found below
Wrapped around a beer bottle

Wrapped around a coke can
