Tupperware seals are unique. They are made of a soft, flexible material with a bellows design. The bellows flexes to accommodate the contents, ensuring a proper seal. Unlike the traditional MM Square, it is not leak-proof, so it is not suitable for long-term storage, but it is convenient for everyday use. Even if you put in something like an apple that sticks out, the bellows seal will still close tightly. - Brand: Tupperware - Color: Yellow - Model Name: MM Square - Size: #1, #2 - Features: Bellows seal Comes with a cute tomato keeper as a bonus. Please use it on your desk or tabletop. The instruction manual included with this product inexplicably contains instructions for a ball. The staff has included the ball's instructions for all products. Since the materials are exactly the same, please read it as a substitute for the MM Square instructions. Thank you for viewing.