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Q: Are the silicone sleeve and lid safe?

A: A good way to test the quality of any silicone product is called the "pinch test". Basically you pinch the silicone, if it turns white- you've got a low quality silicone on your hands. Our cups are made with silicone that passes the pinch test, and the strenuous LGFB standards for silicone products in Europe. The low quality silicone is actually not even allowed in Europe. U.S. regulations are outdated, many of the silicone products we use in the U.S. are low quality and can leach harmful chemicals.

Q: Are the cup and sleeve dishwasher safe?

A: Yes

Q: Is the cup fragile?

A: Yes, its made of glass and inherently fragile. We're working on some new designs for future cups that will be a little more robust.

Q: How tall is this mug?

A: About 7.5 inches with lid on.

Q: How tall without lid on?

A: 6.75 inches

Q: Is the lid spill proof?

A: It has a small hole like a Starbucks cup that stays open but it doesn't leak and is super easy to wash and keep clean.

Q: Could I fit a glass straw through the hole in the lid of the Chuester double walled drinking glass? What kind of glass is this made from?

A: You can fit a straw through, but it was not originally designed for that purpose. It is made from borosilicate glass. We chose Borosilicate glass because it is known for having very low coefficients of thermal expansion making it resistant to thermal shock, more so than most other common glass.

Q: Where is this made?

A: It was designed in Chicago, and manufactured in China. If you're worried about quality, don't be. We actually trashed the first 1000 units from the supplier because the silicone didn't meet our standards. The lid and sleeve are now made from gas phase silicone that meets the European LFGB standard for safety (more strict than the FDA standards).

Q: How long does it keep liquids warm?

A: Most customers say it keeps drinks warm for a couple of hours. How long a drink stays warm depends on a couple of factors though, such as starting temperature of the liquid and ambient temperature outside of the cup. Keeping the lid on will help your drink stay hot longer because it prevents heat from escaping out the top of the cup.