These excellent tencel fitted mattress protectors are as cool as linen soft as silk strong as polyester warm as wool and even more absorbent than cotton tencel is a naturally hygienic fibre made from wood pulp and cellulose and is 100 biodegradable the wood used comes from tree farms practicing sustainabilitythere is also a breathable and 100 waterproof polyurethane layer the unique moisture absorption capacity draws away moisture to enhance comfort as you sleepthe super sm