Without a double the best foam for a Pop-Top. There a 3 elements to support Firmness, Density & Volume. Given most Pop-Top are less than 5cm thick one of the three elements (volume) is greatly reduced hence why a firm, high density foam is a good choice. Don’t be put off with the notion of firmness. It support that matters. Our customers have told us that without a doubt this is the best foam they have ever used in a Pop Top.