Tumbleweed Doctor Definition 20 Ounce Ceramic Coffee Mug Mug is Microwave Safe. Careful: sometimes mugs can be hot. Handle all hot objects with caution. Large coffee mug, measuring approximately 3 3/4 inch top rim diameter x 4 3/4 inches tall; ideal for holding your favorite beverages safely. Made from quality, durable ceramic, this is the perfect drinkware mug or office decor mug to hold pens, pencils, paperclips and candy. All Tumbleweed Mugs hold approximately 20 ounces, perfect for coffee, teas, and hot chocolate. Hand Wash to ensure mugs and mug designs last for years to come.