This breast milk cooler has the ice packs built in - you place the whole thing in the freezer and take it out when you're ready to use it.

Here you can see the built-in ice packs.

When you're ready to use it, you take it out of the freezer and zip up the bottom.

This breast milk cooler holds up to six Medela breast milk bottles. Taller bottles may not fit.

Then you just zip up the top and you're ready to go! You can check this cooler out at the below link.