With the Quick Click Seal, Take longs lids click into place letting you know when contents are secured. The lids have ridges for easy stacking, and the bases have graduation marks for handy measuring. Safe to use in the microwave and freezer, the Take longs lid design allows you to worry about one less thing. If you hear the click, you know your seal is secure. Take longs can easily be washed by hand using hot soapy water, and it's safe in the dishwasher top rack.