Tupperware CrystalWave Plus Vented 2 Cup Container Soup Mugs 2 Pc Guava Color

CrystalWave® containers are made of a heat-resistant material, microwave safe up to 248°F/120°C. The lid's valve allows steam to escape during reheating, preventing any potential pressure build-up. Simply pop the steam vent and leave the seal in place to prevent splattering and spills when reheating.

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