Varilux Lenses from Duffens Optical

This is a nice mug from an optical supply company named Duffens Optical. On the main side is a drawing of a set of spectacles with bifocal lenses.  Both bifocal lenses have a large X over them.  Below the drawing is a dark rectangle.

On the reverse of the mug is a stylized design of an eye with 'Naturally COMFORTable' above it.  Below is the name DUFFENS Optical and the phrae "Helping Professionals Deliver Their Best."

When hot liquid is added, both the bifocals and the Xs clear as well as the rectangle.  Behind the rectangle the phrase "VARILUX COMFORT" is visible.  

Great color change and a great design.  This is one of the few mugs with more than one color thermochromatic ink.  The bifocal design is a dark brown, and the Xs and rectangle are a near  black color.  

DESIGN:  1 Sided
THERMOCHROMIC: 2 Color
TYPE: Corporate Freebie