These pints are insulated with a gel that is similar to the kind inside your ice cream maker bowl. You freeze the container until it's frosty, then fill it up with homemade or storebought ice cream. It will keep the ice cream firm for at least an hour and a half, which should be enough time to get to the park and to dessert-time.
We really like these, since you can also use them for just storing homemade ice cream leftovers; they're definitely not a summer-only gadget.
But we're curious: have you used these insulated pints? Do they work as advertised?
Here are a few sources for these pints, in different colors: