I just measured the diameter and went to the supermarket with a tape measure. I used it so rarely, I've misplaced it. Time to buy another if I do not find it.

William

    I bought a rubbermaid container with a cover that fits perfectly. Use it
    when washing and cover my tuna salad when not.

  do you remember the rubbermaid part number?  should be stamped in the plastic..
  thanks
  chris