This is a BEAUTIFUL VINTAGE coffee/tea mug from the Polish pottery studio Ceramika z Boleslawca.  This is their design #500, and it was handmade by W. Laiusek.  This mug is signed and numbered.  It has an AMAZING hand-painted design of blue waves and edging with colorful yellow and red flowers.  It really is BEAUTIFUL!  This mug is about 3.75 inches tall and 3.75 inches in diameter.  It is in EXCELLENT CONDITION!  There are no chips, cracks or scratches.