Seamless, sleek design. Leak-proof cap. Convenient to carry. Easy to clean. Do not use this product in a microwave.The bottle is to be washed with hot water after every use, fill it up with warm/hot water and soap and screw the cap on.Give it a few shakes then let it sit for a couple of minutes.Rinse it out and let the air dry.Do not use rough surface or steel scrubber to wash the outer surface of the bottles to avoid scratches or chipping of colour.