Our Terra Pure Yoga Mats are specially constructed with two different textured sides to enhance comfort and versatility for your own personal preference. Their closed cell construction allows for excellent grip with a strong grounded feeling while the low compression set foam protects your body from bruising on hard surfaces. This newly developed material is composed of carbon and hydrogen and is referred to as thermal plastic elastomer or TPE. Not only are these mats biodegradable they are extremely environmentally and skin friendly. They are much better that Natural Rubber mats! Natural Rubber may cause extreme allergic reactions!