Calling all mermaids! If your birthstone is a sea shell, then you will adore the iridescent hues of blue and purple in this fantastical finish.Thanks to Swig's triple insulation technology, this tumbler keeps drinks cold for up to 24 hours and hot up to 12 hours. The cup holder friendly, slim shape makes it perfect on the go or at home. From sweet tea to hot toddy's, this Swig will definitely be your new fave!Keeps drinks cold up to 24 hours and hot up to 12 hours.