STURDY & SAFEThese cute cups are made of high-quality safe borosilicate material, Lead-free, and BPA-free. Made of thick clear glass, this sturdy glass cup can withstand the temperature difference between -68~212. So, due to their sturdy quality, such glass tumblers is dishwasher safe that can be used safely for a long time. If you want to make some DIY glass, these 16oz glass cups with lids and straws will be a good choice.