This is the largest size 404 4 QT mixing bowl by Pyrex in solid opal white milk glass with no decoration. This plain white bowl is unmarked, but clearly Pyrex. It was made in the 50s for only one or two years, making the opal undecorated bowls difficult to find. The bowl is 10 1/2" wide and 4 3/8" tall. It is in very good, gently used condition with utensil marks from use. There are no chips or cracks, and the glass finish is glossy and bright.