This is a wonderful example of the Shape 3812 "Melon bowl" in the rare matt grey glaze. This bowl is the large size which means that it is 14 inches in diameter.
The problem you usually find with these bowls is that they are used as fruit bowls and, over the years, the fruit causes the glaze to badly oxidize in the central bowl. This one, however, has near perfect glazing in the bowl which is impressive when you consider that it is almost 90 years old.
The one imperfection is a very small glaze skip on the rim (less that 0.5in) but try finding another one in grey in this such good condition.