I used the insulin cooler by DISONCARE during my 30ish-hour travel to India. And they delivered what was promised. My insulin was at a safe temperature throughout the flight and in warm Indian weather.
I have actually been using their cooler for the past couple of years. This one specifically for the last 6 months. It's not only stylish but works incredibly well to keep my insulin vials and pens insulated. I have used this one for a lot of weekend hike trips in summer and is very easy to travel with. 11/10 recommend.