1940's Pyrex Primary Colors Yellow Mixing Bowl 404 No Size or # Markings Vintage

Vintage Mixing Bowl Pyrex Primary Colors Collection Yellow Size 404 Circa 1940's Bowl No Size or # Designation See Below For Dating of Pyrex Bowls 4 Quart Size Good Condition Shows Wear and Scratches See Pictures 10-3/8" Across x 4-5/8" Tall Thank You For Looking

So I Am Certainly No Expert But My Research Has Shown That The Original 1940's Bowls Had No Numbering And No Pint or Quart Size Designations The 1950's Bowls Had 400's Size Designation But No Pint or Quart Designations The 1960's - Early 1970's Bowls Have Both 400's Size Designation And Pint and Quart Designations Around 1975, The Bowls Started To Have Metric Designations I Hope This Information Assist You In Your Collecting Endeavors