When a latex foam mattress is made using only the milky fluid of the rubber tree, it is called a 100% natural latex mattress. Many manufacturers pretend to make a 100% natural latex mattress but blend in cheaper synthetic latex, which is made from petroleum (SBR-styrene butadiene). The reasons for doing so are simple; synthetic latex foam is easy and quick to produce at a fraction of the cost of natural latex foam. It can also help to stabilize the natural latex. Synthetic latex mattresses however can off gas chemicals and volatile organic compounds which makes them unhealthy to sleep on. Khun Mattress doesn’t take any shortcuts when it comes to your health and refrains from adding synthetic latex the foam. We use natural latex milk only from rubber farms in the South of Thailand. But we prefer to be completely honest. It is just impossible for any natural latex foam producer, to turn natural latex milk into a foam without adding some ingredients such as soaps and foaming agents. You can compare it to baking waffles. You can't make waffles just by pouring milk into your waffle iron. You will need to mix in other dry ingredients (i.e. flour) so your batter will actually turn into a yummy waffle when you bake it. So to be able to bake our foam, we add some ingredients to the latex milk (=vulcanisation). These ingredients are not harmful for your health, but they are there and their percentage needs to be taken into account. Khun Matress foam is tested by the Rubber Authority of Thailand to have a minimum of 96% natural latex, and no more than 4% additives. This is one of the highest percentage natural latex in the mattress industry, your sleep just won’t get any healthier than that.