A set of 4 High quality 16 oz Mason Drinking Jars/mugs with stainless steel lids and straws. The stainless steel lids come with silicon O-ring seal and straw hole plugs on the lid to prevent liquid from leaking. Keeping the drinks cold and refreshing. Great for picnics, parties, outdoor events. Best use with room temperature or cool/cold liquids, and not recommended using for warm/hot liquids with temperature higher than 80°C or 176°F. .