Denby Double Dip Mugs Fire Double Dip Mug Is part of the collection of Denby Dinnerware, proudly handcrafted beautiful tableware. Denby Stoneware and Denby Crystal, has always been about creating beautiful and practical tableware that?s designed for modern life. Denby Dishes are safe in the oven, microwave, dishwasher and freezer. Designed for living , made to last. Made in England.