NWT Tupperware 4 pc CrystalWave Plus set are stain resistant (simply rinse stain out with cold water prior to washing), includes two 4 cup rectangular, 3.5 cup round and a 2.5 cp round containers, each with seals with push open steam release valve. Keeps microwave clean, no splatters! BPA free, Microwave reheat, dishwasher safe and come with the limited lifetime warranty.