OLPRO Husk Baby Mug perfect for Drinks on the go. Created using environmentally friendly & sustainable materials. Available in: Blue, Green, Orange & Pink Materials: Husk & Silicone Freezer Safe Microwave Safe (Up to 3 Minutes) Can safely hold liquids from -30 to 120 degrees Celsius BPA Free What is Husk? Rice Husk is the protective shell which covers the rice grain whilst it is growing. What once was an agricultural byproduct has now become a sustainable material used for fuel, building, and can be made into an alternative to plastics. Husk is perfect for use for our range of drink ware and tableware due to its durability, insulating properties and high density which prevents the growth of bacteria or mold. It is also fully biodegradable.