DIY mattress cores made of certified organic natural rubber latex. No bonding agents, no artificial scents, no formaldehyde, no phenols, no pthalates, no toluene, no benzene, no benzothiazone, no silica containing dimethyl sulfate, no artificial vanillin containing petroleum, no flamebreaker containing silica (dimethyl sulfate), no pesticides, no PBDE’s, no boric acid, no chemical flame retardants , no polyethylene, no polyurethane. You supply your own cover. Used successfully by many with MCS.