The Opal is an elegant but robust bone china mug which we decorate by direct screen printing. 100% dishwasher proof. This product is treated with our patent protected, fully certified AntiBug® treatment to keep germs at bay. The specialist surface starts to fight germs as soon as they come into contact and has been clinically proven to kill 99.9% of harmful bacteria from 50 common organisms such as MRSA, E.coli and salmonella and will continue to fight for the lifetime of the product.