Funny Mug - Keep Calm and Teach Math - 11 OZ Coffee Mugs - Inspirational gifts and sarcasm - By A Mug To Keep TM A Mug To Keep is a registered trademark of Fred And Levine. PRINTED ON BOTH SIDES. High quality ceramic. Treat yourself or give as a gift to someone special. Safe for Microwave and dishwasher. Resistant for house and restaurant use. Large, easy-grip handle Great gift for your best friend, dad, brother, boss or boyfriend. This represents an affordable novelty they will appreciate for years. Ideal to show your love on Valentine's Day or to give a nice surprise on a birthday party.