18-20 Layers System with a Thick Entire Mat Layer of Natural Amethyst from South Korea and Brazil. Crushed & Polished A+ 3-9 mm Gems are Fixed Without Glue by Durable Heat Resistant Mesh Fabric. 27 pounds (12 kg) of Crystals per 29 by 74 inch (72x186 cm) Healing Mattress - Highest Value in the Industry. The Heating Area with Gems is 59 by 26 inch (148x66 cm). Heavy Duty Industrial Grade Parts & Materials. 2-Years Warranty. 10 Years Life Span. No Harmful Emissions, Smell or Off-Gassing.