Permits dribble-free drinking without the need to sit up or raise the head. Placing a finger over the vent hole in the cap controls the flow of liquid through the mouthpiece. The design reduces the amount of spilled liquid should a mishap occur. The hole in the mouthpiece is large enough for a straw. Graduated at 4, 6 and 8 oz. levels. Dishwasher and autoclave safe.