Vented to allow steam to escape. Reduces dribbles and spills. Open sip-through design. Fits: 10-, 12-, 14-oz Foam Cups; Material(s): Plastic; Color(s): White; For Use With: Dart? 10 oz, 12 oz Small Drink Cups; Dart? 14 oz Big Drink Cups; Dart? 12 oz Thermo-Glaze Cups.