I have glasses just like those without the logo. Mine are made of borosilicate glass which is hot/cold tolerant and can be used for brewing Iced coffee in the cup.
My major problem with washing them in the dishwasher or in the sink was getting water inside -- between the two layers of glass. I solved that problem by putting a little dab of clear silicone caulk on the spot on the bottom where the blowing tube was once attached.
The glass is strong for its thickness, but it is very thin and therefore if the glass is tapped against anything hard, it will break, so be gentle with them. I am careful with the spoon and prefer to use a plastic spoon when stirring my beverage.
The shape allows them to be stacked.
8 months ago
Northern, VA, USA